Q&A with Dr Andrew Clark

In April 2010, Andrew Clark offered Mumsnetters help and advice on how to deal with their children's allergies.

Dr Andrew Clark is a consultant in paediatric allergy at Addenbrooke's Hospital in Cambridge. Dr ClarkDr Andrew Clark is behind the recent advances in tolerance induction for children with peanut allergy, his other research and clinical projects focus on improving the clinical care of children with food allergy.

Peanut immunotherapy trial | Caring long-term for children with nut allergy | Referral for allergy testing | Allergy testing | Allergy testing for siblings of allergic children | Food allergies | Causes of allergies | Weaning advice | Reintroducing foods | Vaccinations and allergies

AndrewClark: Thanks to you all for the opportunity to answer your questions, there were so many! I've tried my best to answer you individually, but there were a few themes that came across which would benefit from some general explanation up front.

Also, apologies where I have not been able to answer you directly about your own 'allergy case', you will understand that the one-way nature of this interaction is not the same as doing a face-to-face allergy consultation complemented by testing. One or two of you really need to see an allergist and I have made this clear in my responses. 

One important theme, which many of you raised, is access to decent allergy services. It is clear many of you are making do with inadequate support from your local medical services. Part of the problem lies in education: doctors are not taught about clinical allergy at medical school, which is surprising considering allergy affects a quarter of the population, so all doctors will eventually have to deal with it in some form or other.

We have been caught out by the massive rise in allergy over the past two decades and improvements in allergy care have lagged behind. One important and simple improvement you can make is to arm yourself with information on allergy and there is no better place to start than the Anaphylaxis Campaign (http://www.anaphylaxis.org.uk/home.aspx).

Peanut immunotherapy trial

AndrewClark: There were many questions about my peanut immunotherapy trial (tatt, KerryMumbles, bridewolf, beggsie, LadyBlaBla, TopiaryGirl, lukewarmcupoftea, Lee 36, Chandra, christie2, countrygirl831).

We have completed this in 21 children: 19 can eat five peanuts a day, the remaining two can eat one to two per day without reacting. Some of them have reduced intake to five peanuts once to twice per week and still tolerate them. We hope to reduce this further in the future.

We now have Government funding to perform a larger randomized and controlled study of 104 children aged seven to 15 years, this is fully recruited and we are not taking any more names.

In this study each child will undergo peanut immunotherapy, so it will give us enough data on effectiveness and safety to give us the confidence to start providing this as an NHS service from our clinic within three to four years, if all goes well. Please note this is not a clinical service at present.

It is not likely that this will be available elsewhere in the country for some considerable time. There are two reasons: first, no one else has announced any interest in studying peanut immunotherapy, and second, there are very few centres with the necessary expertise to set up such a service.

I do hope more centres become interested, and I'm sure after we release the results of the next study there will be a surge in demand and interest from elsewhere.

Many of you asked about other scenarios where immunotherapy could be used, for adults or in tree nut allergy for example. We are planning to study tree nut immunotherapy in the future, but this will be done after we have become confident that peanut immunotherapy is worthwhile and safe, so not for at least three to four years and then we will need to run similar studies. Immunotherapy against multiple nut types is going to be more complex and expensive, but it affects a third of nut allergic children so we do intend to pursue it.

I cannot speak for the adult allergists, but I have not heard of anyone who is performing peanut immunotherapy trials of older teenagers and adults.

Q. KerryMumbles: In Dr. Clark's trials how many children have had severe or anaphylactic reactions to the desensitisation process? Will this 'cure' be appropriate for all peanut allergy sufferers? Is touting a 'cure' responsible if it is not appropriate for all peanut allergy sufferers?

How is this treatment protocol different from other desensitisation treatments that have resulted in anaphlactic reactions, even deaths? What children would be considered good candidates for this 'cure'. Who is funding your reasearch?

A. AndrewClark: None of the children have had a severe reaction to immunotherapy. Usually there is mouth itching or tummy ache which lasts a few minutes.

We have treated a small number of children, the larger trial will identify factors which will enable us to decide if all peanut allergic patients are suitable. We did, however, include children with high severity and sensitivity in the original study and these children have developed tolerance to peanut.

The current trial has enrolled children aged seven to 15 with a history of peanut allergy; we have not excluded children on the basis of severe reactions or otherwise.

It is our hope to cure peanut allergy, to aim for less would not be in our patients' best interests. There is much to learn and we are committed to studying this for the extremely long follow-up periods required to ensure that a cure has or has not occurred.

No person has died as a result of oral immunotherapy. Older trials of injection immunotherapy have understandably been associated with more severe reactions.

We are indebted to the Evelyn Trust, a Cambridge medical charity who paid for the salary of our PhD student who ran the challenges in the pilot study. The Evelyn Trust supports many excellent clinical trials in Cambridge.

The new efficacy trial is funded entirely by the Department of Health via the National Institute for Health Research (Efficacy and Mechanisms Evaluation funding stream). This provides funding for salaries for a nurse, research scientist, clinician and partly my own for the three years it will take to complete the study. It also funds 'consumables' such as laboratory chemicals, computers, travel expenses, University overhead costs and the peanut flour!

All the studies were carried out on the Wellcome Trust Clinical Research Facility in Cambridge, this is a separate fully staffed and equipped facility at Addenbrooke's which is free of charge to researchers.

Q. bridewolf: How have the first batch of children coped with life after high tolerance level reached? Have they acepted the daily tolerance dose, and have any forgot and reduced their tolerance level?

How long will you monitor these children over the years, to confirm that the tolerance is life long, and stays at a high level? Do you think that these children would be able to give up carrying epipens?

Does the treatment have a positive knock on effect on thier other allergic diseases, such as asthma, or any other food allergies? I have been told that this treatment , if sucessful will take some years before its widely avaliable, in about 20 -30 years. Is this correct?

A. AndrewClark:The families say it has changed their lives, even those who are allergic to other nut types (peanut seems to be the most difficult to avoid as it is the most prevalent nut type in our diet). The children did not initially enjoy eating peanut, they mostly had a food aversion, which was very pronounced in some. However, over time they seem to become accustomed to it, and some were quite ingenious in how they 'dressed' up the peanuts to make them more pleasant to eat.

These children will be followed up for however long it takes. Our hope is to stop regular intake eventually and follow them up from there with regular testing.

As they are still enrolled in a clinical trial we have asked them all to hang on to their adrenaline injectors, however, our hope it that once they are off treatment then they can forget about emergency medication.

We haven't seen anything that would make us think that other allergic diseases have been influenced by the immunotherapy, but I would say that it has definitely not made anyone worse!

The treatment will take time to filter to the rest of the country. This is because the infrastructure of paediatric allergy is pitifully small, with only a handful of centres around the country- mostly concentrated in the South and East who have the skills and expertise to carry children through this protocol. No one else is developing a similar protocol, so I'm afraid it will mean the patients travelling to Cambridge for quite a few years.

Q. Beggsie: My five-year-old son is allergic to Brazil nuts (identified through one clinical reaction - no breathing issues but mild swelling around the eye). He carries anapens for this. Skin prick tests show at present he is not allergic to any other tree nuts or peanuts. He doesn't have asthma or eczema. How likely is it that desensitization will become available for tree nuts?

In your opinion, should he be eating those nuts to which he is not allergic? At present we avoid all nuts like the plague, but I have heard differing advice/strategies. Same question for those annoying 'may contain' labels. Once desensitisation occurs in the peanut trial, is it necessary to eat small amounts of nut everyday?

I look forward to hearing your answers (and to those other questions) - your work gives me and others great hope for the future!

A. AndrewClark: We do plan a tree nut programme, but it will probably not happen for about three to five years. You will appreciate that children are often allergic to multiple nut types and so designing a protocol for this is more tricky.

Eating other nut types is generally discouraged, but you will hear conflicting advice because there is no evidence base for either approach, just an educated guess. The danger is, of course, that your child could become sensitised to the new nut type, although others argue that regular ingestion prevents this (so the question is then "well, how often should he eat them?" and there is no answer to that one, hence the confusion). Overall, if it's not too much hassle I advise to avoid all nuts.

'This may contain…' labels drive you mad, I know. They just signify a risk, which is real but very small and that risk is difficult to quantify because the food industry just doesn't know how much nut accidentally gets into foods.

However, you can make some sense of it by thinking that some foods, eg chocolate, biscuits, cakes and bread are higher risk, as these are often made in nut-containing versions. Other foods with 'traces' labels on, such as orange juice are clearly lower risk.

Q. Wheredidmyoldlifego: Very interested in following the results and outcomes of your current research into desensitizing of children and food allergies.

Our son is five, has allergies to sesame, tree nuts (but not sure which ones) and egg white as well as egg yolk. He also had a significant amount of chemotherapy (vincristine, ifosfamide and actinomyscin D) between the months of 3 years 3 months and 3 years 11 months (for treatment of parameningeal alveolar rhabdomyosarcoma).

We had been told his allergies would go or at least decrease upon finishing chemo and his reactions on skin prick test have increased twice now since completion of his cancer treatment.

Any ideas if this means his allergies T1 / T2 cells are so in-bred in his allergies that he won't grow out of the allergies and indeed the chemo did not get rid of them?

A. AndrewClark: I have looked after a couple of kids who have had peanut allergy persist through chemotherapy, which makes me think that it is the norm. I don't need to tell you that chemo works by knocking out the rapidly dividing immune system cells. The problem is that once established, allergy is kept ticking over by some very lazy plasma cells, hiding away in the bone marrow, which aren't such a target for chemo as they don't divide very often. Hence these cells may be able to survive the chemo and so the allergy emerges once again (this is speculative, but makes sense to me- I do intend to run it by one of my oncology colleagues!).

I can't think of a reason why such children shouldn't respond to peanut immunotherapy, in fact we are about to start immunotherapy on a teenager with peanut allergy who has been through chemo, so watch this space.

Q. LadyBlaBlah: DS1 is allergic to peanuts and almonds and I am beyond excitement that at some point in his life he will probably be desensitised. I just hope it is before he enters drinking /takeaway food stage of teenager-dom, which is where my worry is concentrated!

I said to him recently that there is a trial going on that may 'cure' him of his allergy and his response was "I don't want to be cured. I like my allergy. If there is something I don't want to eat, I just blame it on my allergy!" It's like he has read the Daily Mail.

A. AndrewClark: Thank you, the children who have been through the study say it is about more than just eating peanuts again, they say their lives have changed as their whole approach to buying and eating foods is so much more relaxed.

Q. topiarygal: Do you plan to widen the desensitisation programme to tree-nuts? After extensive testing, my child's been diagnosed as iodiopathically anaphylaxic as no cause can be found for some of his reactions. Can you see a time when we can simply stay the reaction of the body, irrespective of allergen trigger?

A. AndrewClark: We do plan to widen the desensitisation programme, but this is at least three years away. This is an active area of research from academics and pharma, there are important advances being made, but we are probably 10-15 yrs off a real 'cure'.

"This is an active area of research from academics and pharma, there are important advances being made, but we are probably 10-15 yrs off a real 'cure'."

Q. lukewarmcupoftea: I was just wondering if there was any possibility of the desensitisation process being applied to other allergies? I'm thinking particularly of dairy and egg, both of which trigger an anaphylactic reaction in my daughter and I suspect she won't grow out of this as it is such a strong reaction.

A. AndrewClark: There are some studies on this from the US and Germany (Burks, Beyer, Skripak, Sampson et al) which show some benefit and David Luyt from Leicester is doing some cow's milk trials.

Q. Lee36: Are we realistically looking at a 'cure' for peanut allergy with your work? Should we have some kind of public awareness campaign about the dangers posed by food allergies? My DD has a peanut allergy and it can be very hard to get people (eg in schools/on airlines) to take this seriously and understand this allergy can kill - it's not just me being a fussy parent.

A. AndrewClark: We would like to cure it and that is our aim, although the studies need to run for 5-10 years at least before we can tell. At the least we can get kids to the state where they can tolerate huge amounts of peanut ingestion without reacting. Ourselves, the anaphylaxis campaign and many others are constantly lobbying on behalf of you all to increase awareness of allergy. Over the years it has improved, particularly in schools, but there is a long way to go.

Q. Chandra: When are these trials expected to be completed, results provided and if successful, is there any timescale about how and when this treatment can be made available to other areas?

A. AndrewClark: The trial will take three to four years from now and from then we are likely to offer it as a treatment. No one else in the UK is developing this so I would think it is unlikely to be offered elsewhere for a long time.

Q. christie2: My DD is 13 and has anaphylactic reactions to both peanuts and sesame seed both requiring an EpiPen to be used. She has been retested several times (at five and 10) and we were told that she will have this condition for life and there is no hope for her in terms of growing out of her life-threatening allergies.

But I read about these desensitisation trials and wonder what the future holds as it is promising. But when we both mentioned the UK trials to her allergist doctor (in Canada) he said she was not a candidate for these trials and would not discuss it further.

My questions, is a desensitisation trial out of the question for her and why ( does it only work for some candidates)? Is it only that the UK is leading in this area and it has not spread to countries like Canada? Is there hope that over time these trials may become more available to all with life-threatening allergies or do we just get on with living with them?

A. AndrewClark: Colleagues are running trials in the US, I am not aware of anyone in Canada. However, if the current trials are successful I'm sure it will be taken up elsewhere.

Q. Bobafett: We have an eight-year-old son with allergies to peanuts, tree nuts, milk and eggs. My question relates to the desensitisation process you have adopted in the peanut allergy trials, as my son became intolerant to soya milk through over exposure when used as a dairy alternative.
He can now only tolerate soya milk for a couple of days before his eczema flares and he begins to come out in hives.  Why is this not the case in the peanut trials? Would my son have a similar outcome if he was to try the peanut desensitisation?

A. AndrewClark: The beneficial effect of controlled repeated exposure in peanut allergy is very clear, albeit on a small number of children. The main difference between the two allergies is that soya more often causes delayed-type reactions which may be less amenable to immunotherapy. I would not say that your son has a lesser chance of success with peanut immunotherapy because of the soya issue.

Caring long-term for children with nut allergy

AndrewClark: I would like to explain a little about the prognosis for peanut and nut allergy. Here in Cambridge, all children with nut allergy are included in a Comprehensive Management Package. This includes accurate diagnosis, detailed nut avoidance advice, provision of and training in appropriate emergency medication, training of schools and nurseries and repeated follow up.

Because we follow up all our 'nut allergy' families we have a large database of information on accidental reactions. We have published three series from this and all were reassuring, the rate of accidental reactions is very low (3% per year, compared to rates of 14-50% elsewhere). The severity of these reactions was also very low, with only 1 child out of 785 having a severe reaction over a 4.5 year period.

"We see more frequent reactions as children grow into teenagers and start making food choices for themselves. We are also beginning to explore ways to target teenagers about these issues directly."

We do however see more frequent reactions as children grow into teenagers and start making food choices for themselves, so I intensify the follow up at that stage. We are also beginning to explore ways to target teenagers about these issues directly; one example of this is an Allergy Camp initiative which I piloted last September.

This consists of an afternoon with moderated interactive sessions aimed at getting teenagers to gain ownership and control their allergy - passing this from the parents to themselves. I aim to introduce Allergy Camp over the next 12 months as part of our routine follow up for nut allergic teenagers at Cambridge.

Q. Spoof: My daughter has a purported peanut allergy. She's seven but was diagnosed at 18 months after blood tests taken to analyse allergies due to a cow's milk protein allergy, and a skin reaction to peanut butter.

We have carried an EpiPen around with us ever since. I don't especially want to put her through any more tests than necessary, because she has various other health complications which means she's poked and prodded enough as it is. How likely is it that she will grow out of this allergy, like she has with the cow's milk protein one?

That said, she hasn't really had any follow-up care/review for her allergies, and I wondered what sort of care you thought should be carried out with children who suffer allergies severe enough to have to have an EpiPen?

A. AndrewClark: Difficult one, as your daughter has never had a clinical reaction. It would be worth a review and re-testing to see if there is still evidence of reactivity. Skin prick tests are well tolerated, minimally invasive and give reliable results. Generally, if the skin prick test wheal is greater than 8mm wide then there is about a 95% chance of clinical reactivity. If the wheal is 3-7mm this falls to about a 50% chance.

Q. tatt: My nut-allergic teenager is rapidly approaching adulthood. Are there any plans to extend the trials to adults? (My teen might want to apply to Cambridge Uni.) We live too far from Cambridge to travel for frequent appointments, especially for a teenager doing exams. Do you have any idea when this might spread to other parts of the country?

And a general allergy question - I've always been told Piriton is the fastest acting antihistamine but came across some research suggesting Benadryl might be. Which does act quickest on allergic reactions?

A. AndrewClark: We are a paediatric team, so focus on children. No doubt when the trials are finished our adult colleagues will get involved, but I have heard of no one starting peanut immunotherapy for adults yet. It really is early days and although we have made good progress, there is still a long way to go before this treatment is available 'near' to everyone in the country. A major part of the problem is the lack of allergists at a national level, compounded by a lack of training for doctors in allergy.

The choice of antihistamine is not so important for acute reactions, we have not experienced problems because one has worked less quickly than another. When used to treat conditions on a daily basis, e.g. hay fever, the relative sedating properties of different antihistamines becomes important. The 'newer' generation antihistamines, such as certirizine, loratadine and fexofenadine have a quicker onset of action and longer duration of action than the older generation ones.

Q. Cornishsmartie: I have a daughter of five who has a severe peanut allergy. Her pre-school skin prick developed a wheal of over 10cm which took several days to disappear. I am enormously excited about the desensitisation program and hope it makes it to Truro before she starts secondary school.

Have you researched alternative medicine with regard to allergies? What is your opinion on kinesiology as a 'cure' for allergies? I have a friend whose four-year-old son used to get terrible hives when he came into contact with the cold (hands/face in winter, whole body if he got wet and then cold) and she claims this was cured by a kinesiologist and she is badgering me to make an appointment.

A. AndrewClark: I strongly support traditional medicine as a means of diagnosing and managing potentially severe allergies. I would not rely on any 'diagnostic' technique that has not been validated against the accepted gold standard used by the traditional allergy community. There is great danger in assuming a disease to be no longer present, when reliable allergy testing has not been done.

Q. bruffin: My son is 14 and has various allergies to tree nuts (except cashew) and sesame seeds and seems to have had a reaction to poppy seeds and sunflower, so he avoids all seeds. He also has hayfever, animal allergies and is allergic to plasters and insect bites. His allergies appeared when he was four when in one weekend he had a reaction to sesame and pecan nuts, and after that started having problem with peanuts etc. At 12 he was tested again and he has grown out of the peanut allergy but not the treenuts or sesame.

He now eats peanuts, is this wrong or can the peanut allergy return? Also, at this age, is there any chance of him out growing the other allergies? Are these allergies inherited, as my husband has similar allergies?

A. AndrewClark: Allergies in older children, especially to the nuts and seeds, tend to be fixed and long lived. The allergies themselves are not inherited, your husband just passed on a tendency to develop allergy.

Q. Brollyflower: In your view is it justifiable or sensible for schools to have a blanket ban on nuts (or even just peanuts)?

A. AndrewClark: I recently helped write a European document on managing the allergic child at school, this included the recommendation that: "Schools should avoid providing food containing peanuts and tree nuts and major allergens relevant to the country, e.g. sesame (including meals, snacks and vending machines). This measure should not be enforced in isolation, but should complement the educational and protective environment for allergic children."

The real point here is that it should be part of a larger coordinated plan to protect the child that extends to all school circumstances (e.g. school trips) and all staff.

Q. countrygirl831: My son has just turned 18 and has had multiple allergies all his life, including peanuts, tree nuts, milk, eggs and even lily pollen. He wants to travel during a gap year, which worries the hell out of me but doesn't seem to faze him. He always carries 2 EpiPens with him and a Medic Alert card, plus Piriton and inhalers.

Would he be able to replace an EpiPen while abroad (Australia or America) if he needed to use one? Do you know of any adult trials taking place?

A. AndrewClark: EpiPen is available in those countries, although you would probably need a prescription from a physician. There are no UK adult trials at the moment.

Q. Holiday123: I have a son who is now 19 and has been allergic to peanuts since the age of 2. I was just wondering as you are doing a desensitisation study that we are doing more harm than good by keeping our home totally nut free as maybe if he was exposed to tiny traces it may benefit his immunity better.

A. AndrewClark: The current evidence suggests that the exposure which causes peanut allergy in the first place is so small that it goes unoticed. Also, peanut allergy is more common in houses with a high peanut consumption, so currently I would say it is better to have a completely nut free house. The desensitisation doses we are using are small to begin with for safety's sake, but the doses which really reduce clinical reactivity are large.

Referrals for allergy tests

AndrewClark: You have two options, firstly you can get access to any consultant in the UK using the NHS Choose and Book system, which requires your GP to make a referral (http://www.chooseandbook.nhs.uk/).

Secondly, there are many consultants who can see you on a private basis. One of the best websites to help find an allergy clinic is that of our parent organisation the British Society of Allergy and Clinical Immunology (BSACI: http://www.bsaci.org/). There you will find a clickable map with a description of clinic facilities.

Of course, you can always come to see me in Cambridge either through the NHS (Allergy Clinic, Box 40, Addenbrookes NHS Trust, CB2 0QQ, 01223 216 645) or privately at the Spire Hospital, Impington (cynthia.burtenshaw@addenbrookes.nhs.uk, Box 181, Addenbrookes NHS Trust, CB2 0QQ, tel: 01223 216 020).

Q. TeamEdward: My husband has a severe nut allergy (all nuts) and our health visitor suggested that we avoid giving our children nuts. My eldest son has just started school and we are worried about him coming into contact with nuts, but on the other hand cannot honestly say to the school: "He has a nut allergy." 

Our GP told us they cannot test for such an allergy unless the child has already had a reaction.
Short of sitting in A&E with a jar of Sun Pat in one hand and bottle of Piriton in the other, what are our options? Is it likely our sons have an allergy? Where can we go to get tested if the GP refuses?

(Background info: my husband is also allergic to eggs. I have no food allergies but have asthma, hayfever and allergy to fur/feathers. Both children have mild eczema.)

A. AndrewClark: This is a common problem without a straightforward solution. A negative skin prick test is useful to say that peanut allergy is not present (on the day the test is done), and peanut could be introduced. Difficulties arise in deciding what to do if the test is positive; as it doesn't really indicate whether allergy is definitely present (this is the problem your GP refers to). Anyway, an allergy clinic should be able to perform and interpret the test for you.

Q. tatt: Some GPs seem to be very poorly informed about allergies. Questions on this site sometimes refer to GPs saying "nothing can be done" or "no tests are available", when it's clearly not true. Even paediatricians are not always well informed (had to give one information from the Anaphylaxis Campaign after being told a test was unavailable). So what can allergy consultants do to help educate them - maybe some articles for the British Medical Journal?

A. AndrewClark: We are always aware of this and trying to engage family doctors but remember they have to be experts these days in everything. The BSACI.org produces primary care guidelines for common allergies, the annual meeting has a primary care day and we also engage with paediatricians.


Allergy testing

Q. ronshar: Well done for your excellent work in Cambridgeshire. As you can see there are so many of us here with allergic children, all needing more information than we are being given by our own health care professionals.

I have three children. My eldest daughter was dairy intolerant as a baby. Tummy pains and eczema linked to it. She also developed a pistachio nut allergy when she was about five, following two anaphylactic reactions. She is now 10 and has an EpiPen. My GP refuses to refer for testing as they are not reliable apparently. My youngest son is 18 months and he is allergic to dairy and soya. But not peanuts as he eats them quite happily.

Is there a blood test that can be done which actually measures the immune system response accurately? If so why is this not offered to children?

Are my children suffering because I have developed allergies to dust, dust mite, birch, cat and dog? Does a mother pass on an immumne response problem via the placenta?

A. AndrewClark: Our generation simply pass on a tendency to develop allergy, the actual allergy that our children get depends on environmental exposure (as yet unknown).

Allergy tests are reasonably reliable and can be performed from infancy, so either skin-prick testing or ImmunoCap blood testing will return a level where one could decide whether an allergy is still present, even years after a reaction. This is how we routinely follow up our nut allergic kids year after year.

Q. Hensor: I am expecting our first baby in 10 days. I have a severe allergy to all nuts and pulses (my principle allergy is peanuts but I have reacted to other nuts as well as soya, lentils, chickpeas etc) and have been hospitalised on about half a dozen occasions. I carry adrenalin pens, antihistamine and steroids with me.

What are the chances that our baby will also have a food allergy and what should I do about having her tested? At what age should we consider tests for her?

I have found in the past that GPs are simply not knowledgeable enough about this condition (this is not a criticism as I realise it is a specialist area) and am worried that early signs may be missed (as they were when I was a baby).

A. AndrewClark: There is not much evidence to guide us here. Your child will have a minimally increased chance of allergy. Whatever happens, eczema is usually the first sign of allergy trouble, so if this is not present then you can relax and introduce foods as planned. If there is eczema, then you may wish to consult an allergist about food introduction in the first year.

Q. orangina: I have a son aged three. He doesn't appear to have any allergies as such, but he does have a viral wheeze/asthma, which he has had on and off since summer 2009. We keep it under control by using his blue inhaler, are not on a preventative at the moment, and he has had about six visits to A&E in the past nine months but has never been admitted.

He eats most foods with no problems, but recently if he has had peanut butter (which is rarely as he doesn't even like it), he starts to cry and hold his throat, and then gets in a panic. It's almost as though he is about to start wheezing. He eats all sorts of other nuts normally (almonds, cashews) as well as flapjacks etc that probably contain then, and has no problem at all. We have no history of allergies in our family on either side.

What do you think? I really don't think he has an actual allergy, but there does seem to be some kind of sensitivity going on here. Should I avoid peanuts to be on the safe side? Should I avoid all nuts to be on the safe side? And if he does have a reaction like that in the future, or even worse, how do I deal with it? With his inhaler? Or a dose of Piriton?

A. AndrewClark: You really need to see an allergist. Please do not give your son any nuts or nut products until he has been assessed. They will be able to rule nut allergy in or out, provide appropriate emergency medication. They will also address his asthma which sounds as if it could also benefit from a review.

Q. QwertyQueen: Aged two, my son had a skin-prick test for peanut allergy and he reacted a lot with a huge welt and as such since then we carry an EpiPen and do all the usual avoidance tactics. He is now three and a half and had blood tests for allergies recently - they tested the serum (that is the phrase the doctor used) and it came back as highly allergic to dust mites and 'borderline' allergy to peanuts. Would this indicate that he may be outgrowing it? My understanding is that it is not an exact science and I should continue as if he is highly allergic.

A. AndrewClark: Allergy tests only indicate the likelihood that the allergy is present and do not indicate severity. It is difficult to comment without seeing the exact test results and exploring your son's history in more detail, but I do not see anything in what you have written to indicate that the allergy has resolved.

Q. tatt: Several people have already mentioned testing but some of have experienced problems with the accuracy of skin prick/ RAST tests. Can I ask you about progress on developing more reliable tests eg more accurate test? and whether you consider skin prick or RAST tests the most reliable? Also whether there is any chance of ever developing a test that will predict not only who will react but how severe that reaction might be.

Also a comment - as the parent of a non-asthmatic child who has had an anaphylactic reaction I am extremely grateful that we saw an allergy consultant who believed in prescribing EpiPens to all those with postive nut allergy tests. Instead of sitting and praying medical help would reach us in time (as I had to do with their first reaction) I was able to deal with the reaction promptly. We can't keep our children away from all allergens, although we can limit the frequency of reaction. I hope you are not one of the consultants who restricts adrenaline to the asthmatic.

A. AndrewClark: Both types of test have their strengths, skin prick tests are well tolerated and the result is instant and robust. Blood testing (Immunocap, used to be called 'RAST' testing) is more widely available in primary care. There is no severity test and I think there never will be an all encompassing one because so many 'extrinsic' factors affect severity (e.g asthma control, exercise, alcohol, illness) and none of these can be factored in to a simple bedside test.

I do support rational prescription of adrenaline autoinjectors, so would recommend them for children with previous severe reactions or with concurrent asthma. There are other circumstances where I would recommend them, particularly as you say when it is clear it will help provide peace of mind where the risk is unknown. Remember, we do not ration the pens, it is your GP who actually prescribes them, very often the patients have them already when they pitch up to clinic. I like to work with the GPs on this and I don't support saturation with multiple pens per patient. IMO, for most children, one pen at school and one in a travel pack outside school should be enough.

Q. Aaarghhh: My daughter (age nine) had blood tests at age seven for her allergies and showed very low levels of IgE but as these were all over the negative classification of 0.35, she was classed as having allergies. However, the consultant said that you can still show high IgE levels, but have grown out of the allergy.

She was initially diagnosed as being allergic when she was five (not allergic before this), where scratch tests were highly positive (peanut 12mm, hazlenut 3mm). She has had three reactions where her face has puffed up (no anaphylaxis). The 12mm scratch test for peanut aged five does not correlate with the ige level of 1.1 when age 7.

However, she has not had a reaction for a couple of years now (perhaps because we are very careful). To make it more confusing, they also tested non-nuts and she showed positive IgE levels for milk (0.42), egg (0.53) and wheat (0.79), but she eats all these with no problems at all.

Is it possible that scratch and IgE tests can be so different or is she growing out of allergy? Should we have more scratch or IgE tests to decide whether to go for the oral testing or not?

A. AndrewClark: There can be a disconnect between blood IgE and skin-prick test results, with low levels of blood IgE being present in patients who tolerate a particular food.

We prefer skin-prick tests in our clinic and find them reliable when following up kids with nut allergy. My practice is to do a challenge when there have been two sequential negative skin prick tests to a nut, separated by three months.

Q. Krispy20: I had skin-prick tests done for my hayfever last year, and they said the result was '8' but I am confused as to what '8' means - is it on some sort of scale? Also, what would this indicate to you about my hayfever?

A. AndrewClark: Skin-prick tests are usually reported in mm wheal diameter, so you may well have an 8mm wheal to grass pollen. This is a positive reaction to grass pollen, which complements your clinical history of hay fever. It does not indicate severity, which is best assessed clinically.


Allergy testing for siblings of allergic children

AndrewClark: Many of you asked about allergy testing siblings of food allergic children, especially for peanut allergy. This is a question we tend to duck in clinic because if we offered sibling testing to all it would swamp the service.

There are problems with interpreting tests in young children who have never eaten peanut, or any other allergen for that matter. A negative skin-prick test gives you about 95% confidence that the child who has never eaten peanut would not react to eating it for the first time. So then you could reasonably introduce peanuts at home (starting by rubbing a small amount on the lip and giving increasing amounts thereafter). What should you do then? Probably the child should continue to eat peanut regularly to keep their tolerance going.

"Many of you are worried that your own specific allergy will be passed on to your children. This scenario is the exception rather than the norm however. If you or your partner have any allergic disease you provide 20% increased risk each to your offspring, but the risk is of 'all allergies', not just your particular one."

The difficulties arise when the test is positive. The tests were never designed to answer this question, so it is not surprising they perform badly, so that many children with a positive allergy test will not react on eating peanut for the first time. The difficulty is that we can't tell without an oral challenge and this is a time-consuming procedure which is not without risk.

So, as I say, for very young children we often put off the question until they approach school age, by which time they've often been exposed accidentally. At school entry, a negative test will be helpful, but a positive test can confuse.

We are constantly striving to improve allergy testing, there are recent developments which might help, including tests which look at allergy responses in the blood to small fractions of the allergen (so-called resolved component diagnostics), but it will be some time before these are validated and available to the clinician.

Related to this is the question of inheritance of allergy. Many of you are worried that your own specific allergy will be passed on to your children. This scenario is the exception rather than the norm however. If you or your partner have any allergic disease you provide 20% increased risk each to your offspring, but the risk is of 'all allergies', not just your particular one.

Generally, most kids will start with eczema in infancy and develop food allergy as toddlers (eg egg, milk and peanut). The explanation is that environmental exposure to allergens contributes an enormous amount to determining the particular allergy, eg allergy to indoor allergens (food, pets) occurs earlier in life than allergy to outdoor allergens (eg pollen) and this is related to exposure.

Unfortunately, we do not understand what exposure, when, by which route etc causes allergy, so there is not much we can advise in the way of avoidance to prevent allergies appearing in the first place.

Q. Gandababies: I wondered what the current advice was for siblings of children with nut allergy.

My eldest child is anaphylactic to peanuts. I have two more children and one on the way, the eldest of which is due to start school in September. We have not fed either child nuts but do allow them products with cross contamination issues when our daughter is not with us. I would like to know one way or another before my son starts school, is feeding him a spoon of peanut butter in the car park at the local A & E the best option or can you advise something different - btw he has never shown any sign of allergy.

A. AndrewClark: Siblings have a 7% chance of developing nut allergy compared to a 1-2% background population rate, so there is an increased risk but it is small. Opinions vary on what to do and there is a poor evidence base to support any one point of view.

One straightforward way to proceed is to ask for IgE testing to peanut/nuts and if this is negative then follow advice on peanut/ nut introduction. The difficulty begins if the test is positive as a challenge may then be required. You can request your GP refer you to an allergist to help with this. What ever you do - don't 'do-it-yourself'!


Food allergies

Q. Skimty: My daughter (18 months) had been skin prick-tested at St Thomas's and has confirmed allergies to peanut, tree nuts (several but unconfirmed which ones), sesame, egg white and raw eggs (although she tolerate cooked egg as an igredient) along with eczema and wheezy breathing. There is very little family history of severe food allergies and neither myself, my husband nor our three year old have shown any allergic reactions. We have been told that she will have to use an EpiPen when she starts nursery. I have three questions:

  • What are the chances that she will outgrow any of these? She hasn't had a reaction since 10 months.
  • I am currently pregnant with my third child. I am confused as to whether to avoid peanuts. Also, what can I do to avoid the new baby developing allergies? I breastfed my daughter and didn't introduce solids until six months but, in hindsight, my own consumption of peanut butter was causing her baby ezcema.
  • My daughter's nappy rash cream contained peanut oil and I used it on her at a few weeks with very sore nappy rash. Could this have sensitised her?

A. AndrewClark: I do not have enough information to answer your first question. Current advice from the Food Standards Agency does not stop you from eating peanuts in moderation during pregnancy. They still recommend you to avoid giving them to your child until they are three years. 

We do not know what sensitises children to peanut, it is possible that skin contact with peanut oil is responsible, but it is equally plausible that sensitisation comes from contact from peanut butter traces on the hands, on bottles or in food. 

Whatever happens, the exposure which causes sensitisation is so small it is difficult if not impossible to avoid, even if we knew what it was.

Q. Squiz: My son had positive RAST test to sesame seeds and a year later to hazelnut, although skin prick tests show negative. At this time he was tested for all nuts, which were negative beside hazelnuts. Since then when he has tried anything with nut in it - brazil nuts, almond (generally in chocolate) he has a reaction which consists of itchy, hot throat, and he vomits if not given antihistamine.

Should we avoid all nuts just in case? Although he has had negative RAST test results for nuts is this because he had never eaten any of them before the tests?

A. AndrewClark: I advise to avoid all nut types, not just the one you are allergic to. The logic is that manufacturers are not great at separating nut types within products. All they have to tell you is that there are nuts in a product, they are not obliged to spell out exactly which types are present. Even if you buy bags of single-nut types, remember that the manufacturers probably deal in all the other nut types as well and contamination is a possibility.

Q. needsdirection: My five-year-old son is allergic to cod (reacted at 16 months with vomiting and hives, runny nose and eyes etc.) When he was three, he had a tiny bite of some cake with hazelnuts in it, vomited, and was covered in hives again. Allergy tests classed his allergies as: class 5: birch, hazelnuts; class 3: cod/plaice; class 2: peanuts, soya beans, and brazil nuts; class 1: egg whites, almonds, tuna.

I don't let him eat any nuts, however, or any fish. I have read, and people have told me, that a nut allergy can be mild (hives) one time and result in anaphylactic shock the next. Is this correct? This makes me extremely anxious most of the time that he's going to come into contact with some nuts and have a severe reaction.

We have also been warned of a cross-reaction because of the birch allergy - carrots, apples. He eats both carrots and apples. Does a cross-reaction mean that they can cause a problem together?

A. AndrewClark: It sounds like you need to see an allergist. To answer these questions fully I'd have to ask a few of my own.

Q. Jamhappi: My son has had an allergy to eggs since he was around a year old. This resulted in his eyes swelling up and a red rash coming up. We stopped him from eating eggs. After tests it turned out that he was allergic to eggs, nuts and some fruits. My son is now five and is happily eating eggs without any reaction. Should we try nuts with him, he same way as we have tried eggs?

A. AndrewClark: No, I would advise you to seek a consultation with an allergist for further management.

Q. Almondfinger: My daughter (2.5) first had a reaction to hummus (sesame seed) at about 10 months. She has had eczema since she was three weeks old, kept under control with cortisone. She is allergic to all nuts and seeds, egg, tomato, shellfish, beef and lamb. How common is it to be allergic to beef and lamb? I thought rice and lamb were the two things one could eat on a serious exclusion diet and work up from there. My husband thinks it's the render from the fat rather then the actual meat. Do you have any thoughts/research on this?

A. AndrewClark: I have no details on how the diagnosis of allergy to beef and lamb were made, so it is difficult to comment, although I would say it is extremely rare to have allergy to these - that is clear clinical reactivity, not just a positive test.

Q. Katisha: Both sons when very young (now 10 and eight) have immediately been sick on eating lightly cooked egg. So we have avoided egg for years. They seem OK with cake now but still can feel a bit dodgy in the tummy after some things that have egg as ingredient, eg ice cream, that turns out to have had egg in it.

I would like to know whether they are growing out of it but am rather loath to feed them omelette. Would it be best to have allergy tests somewhere or just bite the bullet and try to persuade them to try some quiche or something? What I am asking basically is will giving them egg make matters worse or better? 

A. AndrewClark: I would really need more information in order to advise you, but there is a straightforward reintroduction protocol which has just been produced by the British Society of Allergy and Clinical Immunology, you should be able to access this on here later this year (http://www.bsaci.org/index.php?option=com_content&task=view&id=117&Itemid=139).

Q. Babbit : My daughter has a diagnosed peanut and nut allergy after suffering one reaction at the age of 18 months. She has recently turned five and had another RAST test which shows her sensitivity is decreasing (from 2.5 to 1.4). Is it likely this pattern will continue until she is not sensitive at all? (I have been practising complete avoidance of all nuts and products which contain, may contain etc). Is there any correlation in your view between sensitivity level and possible likely reaction to exposure? Can she have ground nut oils?

A. AndrewClark: Again, I'd need more information from you to answer your questions, but to give a broad indication, yes the magnitude of blood test result does give some indication of whether the allergy is still there, but it also depends on other things.

"You clearly have lots of questions and this is so often the way for families who don't get to see an allergist."

You clearly have lots of questions and this is so often the way for families who don't get to see an allergist. It is your right to see the doctor of your choice in the NHS, providing your GP has agreed that you need a referral.


Causes of allergies

Q. OkieCokie: There is no history of food allergies on either mine or my husband's side, although my husband suffers from hayfever. I often wonder why my son has multiple food intolerances and possible allergies to many things including wheat, egg, nuts, diary, oats.

Are there more incidences of food allergies in rural or urban areas? Is there any link between antibiotics being given to new borns and the subsequent development of food allergies and intolerances in babies/very young children.

A. AndrewClark: There is more allergic disease in urban than rural areas. This holds true across the world as we see a rise in allergy prevalence across Asia as communities migrate into large cities to find employment. I am not aware of an effect of antibiotics.

Q. PussinJimmyChoos: What do you think is the cause behind the number of allergies that we are seeing in the modern generation? Do you think that the elimination of so many things for pregnant women is actually contributing to the problem? I appreciate that there are a number of factors to be considered but would be very interested in your view point

A. AndrewClark: There is clearly an inherited risk, each allergic parent adds about a 20% chance of allergy to their offspring. Movement away from the hunter gatherer lifestyle into cities, which has occurred over a relatively short time, means we are no longer exposed to the harmless commensal organisms which we had evolved to tolerate over 10s of 1000s of years. We do not have all the answers, but the movement from the countryside into the city has to play a part in my view.

Q. hobnob57: If a mother has an immune response to a type of food molecule (eg undiagnosed coeliac or similar), she raises antibodies against it. If the antibodies enter breast milk and therefore her baby, does the baby then suffer the effects of the immune response too?

A. AndrewClark: No, the two are only linked by genetic risk; the offspring's chance of allergy is then dictated by their environmental exposure to allergens. The exact exposure, route, dose and timing are unfortunately unknown, but it is thought not to occur through breast milk. In fact, on a population level breast feeding is associated with a reduced prevalence of allergy in offspring.

Q. Weta: Is it true that giving formula to a newborn can increase the risk of allergy? My son had 10ml of formula in hospital shortly after he was born because he was screaming (in incubator) and wouldn't/couldn't feed, and subsequently turns out to have a serious dairy allergy. One paediatrician said that often children allergic to dairy had been given formula in hospital. Is this right?

A. AndrewClark: No large studies have confirmed this, but it has been reported in small-case series. It really is something we need some good quality research on because it would have important implications for how we feed in the first few days.

Q. hobnob57: My background is as a lactose intolerant baby myself, my oldest daughter was gluten intolerant as a baby (both through breastmilk and food) and dairy allergic (still is to some extent, but can tolerate enough to make it not much problem), my second daughter is exclusively breastfed and sensitive to dairy, soy, gluten, egg, nuts and oats in my diet.

Is there any evidence/research being done that links them to environmental chemicals in the mother's bloodstream? What are your thoughts on something like leaky gut caused by Candida in the mother exposing breastfed babies to antigenic food molecules? (I haven't heard of anyone speak of this, but a friend had leaky gut and I'm just wondering what the effects on a breastfed baby may be.

Also, does exposing babies to foods (through breastmilk or weaning) to which they are allergic or intolerant do any potential long-term damage? Am I sensitising them further?

A. AndrewClark: No, the leaky gut has been found to be associated with eczema, but there is no direct evidence to say this is a causal association, it could easily be a consequence of the allergy itself. Cow's milk protein intolerance commonly presents with reflux and eczema in infancy, and if they tolerate the food clinically then you are not doing any damage.

Q. Cakenomore: I would be interested to hear your opinion on leaky gut theories and multiple food allergies. I have read on the internet about the link between increased gut permeability and the body becoming sensitised to food. That certain things can weaken the gut such as an imbalance of unhealthy bacteria. In fact my son of 18 months had thrush in his mouth that we struggled to get rid of due to reinfection through my nipples that had eczema and thrush. Could this have perhaps contributed to his food allergies?

Are there supplements or probiotics that you could recomend for a child of 18 months to strengthen their gut, or do you think that would be a waste of time.

I have also read about rotation diets for multiple food allargy sufferers to help prevent them from becoming allergic to more foods. Does this go against your theories? Would you recomend rotating foods as much as possible or not?

In your opinion should all children with a peanut allergy carry an EpiPen whether asthmatic or not? My son is allergic to peanuts but as has never been exposed to them even through breastfeeding or in the womb I have no idea how he would react if accidentally exposed.

A. AndrewClark: In general kids with eczema and early onset food allergy do have a gut which is more permeable to larger-than-normal molecules. It is possible, though not proven, that this is related in some way to the development of food allergy. There have been several well conducted studies of pro and prebiotics but no of them (alone and when considered together) really show a worthwhile benefit.

It is difficult to judge who will benefit from an adrenaline autoinjector, certainly those with previous severe allergic reactions or asthma, but for others the prescription may be made on the basis that is could give peace of mind.

Q. LoveBeingAMummy: My daughter, who has just turned two, seems to have developed a reaction to banana, it started in August last year.

Basically, if she ate banana, the next morning when she filled her nappy it would result in almost a burning of her skin. Before this she had eaten them without any reaction, and certainly never ate them excessively. Even a small taste of banana ice cream caused a reaction.

Is this a common allergy, as I had not heard of it before? Also, I suffer from hayfever and wondered if this means she will be more likely to have allergies? What if anything should I do, apart from keeping her away from bananas (if that is the right thing to do)?

I also wondered if there is anything I can do with regards to hayfever? I would hate for her to suffer from this. My mum knows the exact moment that triggered my hayfever and I would like to avoid any thing like this for my daughter.

A. AndrewClark: Banana is an unusual cause of allergic reactions, and I would need some more information from you and to perform some testing before confirming the diagnosis. It may be another food is responsible.

Allergies are not passed from mother or father to child directly (ie having a parent with hayfever does not mean that of all the allergies you will develop hayfever). Rather, your parents increase your risk of developing any allergy, the allergy you actually get is up to you - and we have no way of preventing this happening at present.

Q. Yellowbutterfly: Can a food allergy or intolerance cause constipation as opposed to diarrhoea? The reason I ask is as follows. My daughter was born at 34 weeks. She was initially exclusively breastfed and passed nice breast milk stools. The day before her discharge, supplies ran out and she was discharged on SMA prem 2. This led to immediate constipation.

After two weeks we were advised to change her milk to Neocate (the doctor seemed to latch onto the fact that I have eczema and am allergic to animal hair). We changed to Neocate and things did not improve. We gave lactulose and water, still no improvement. After six weeks we changed to Aptimil first milk. However, my daughter is still constipated, by this I mean she passes yellow, very hard "adult like" stools. Lactulose seems to work occasionally, water helps slightly. DD had subsequently been diagnosed with reflux, also.

As food intolerances/ allergies usually cause vomiting and diarrhoea, I was wondering if in your experience you have seen them cause constipation?

A. AndrewClark: The simple answer is 'yes', food intolerance can unusually cause constipation, and it is well recognised by allergists. Although in your case I would be cautious about making this link because all symptoms attributable to cow's milk protein intolerance should really have resolved once your daughter had started neocate, but they did not which makes one wonder if it really was the cow's milk protein which was responsible.

Q. brightspark2: Arachis oil is in many baby products. I found out this is the Latin name for peanut oil. Could overuse of these oils and creams in the past have contributed to the prevalence of peanut allergies now?

A. AndrewClark: It is possible, but not proven. The evidence suggests that the dose of peanut that causes 'sensitisation' and eventually clinical disease is small and goes unnoticed when it is first encountered, so it is tempting to blame arachis oil.


Weaning advice

AndrewClark: Delaying introduction of allergenic foods has been the mantra for allergy prevention over the past decade. There is a poor evidence base for this approach, yet we are stuck with a lack of evidence to promote early weaning.

However, help is at hand for future generations at least, as Dr Michael Perkin from King's College is running a seven-year study of early weaning of common allergy-causing foods. Alongside, Dr George du Toit from the same institution is running the LEAP study, which will hopefully indicate when we should introduce peanut into our childrens' diets.

Q. LaDiDaDi: My daughter, aged four years, is allergic to lentils, peas and soya beans. She is to be tested for allergy to chick peas, other legumes and tree nuts, all of which I currently avoid in her diet.

I have a four-month-old son who is currently exclusively breastfed. Would you advise waiting until six months before weaning and then not introducing the foods that my daughter is allergic to until nearer one year, or do you think that the overlap between breastfeeding and introduction of allergenic foods is more important? In which case I would introduce these foods earlier as I plan to stop breastfeeding when I return to work when my son is nine months old.

I would also add that I am a vegetarian and the foods that my daughter is allergic to feature heavily in my diet and I probably introduced them to her diet when she was weaned at six months.

A. AndrewClark: Weaning should usually take place from about six months, there is usually no 'inheritance' of the same allergies, which allergy the child gets depends more on environmental exposure. I would have thought it sensible to introduce the foods you want from six months.

Q. Icedcake: I would really like to know the answers to the following from Dr Clark's perspective/research:

  • Should you wait until six months OF BF/FF to introduce solids to a baby and why?
  • If you early wean before six months then what are the risks of allergies?
  • Is there any link between reflux in babies and allergies?

A. AndrewClark: The current WHO advice is for six months of exclusive breastfeeding followed by weaning. This is based on the observation that at a population level this intervention reduces the prevalence of allergy. Thus it may work for your neighbour but not you; overall in the community there will be a reduction. We do need more detailed studies to identify characteristics in a family which would predict a good response to delayed weaning.

"Milk intolerance can present in infancy with an irritable, colicky, vomity baby with eczema, who does not sleep.Time and again these babies do not receive a diagnosis until the family has suffered many months of sleep deprivation. I am always encouraging doctors and health visitors to think about cow's milk intolerance early in babies with this clinical picture."

The link with reflux is that milk intolerance can present in infancy with an irritable, colicky, vomity baby with eczema, who does not sleep. Time and again these babies do not receive a diagnosis until the family has suffered many months of sleep deprivation. I am always encouraging doctors and health visitors to think about cow's milk intolerance early in babies with this clinical picture. A simple change of milk to soya or a hydrolysed formula can fix it.

Separately, so-called 'silent' reflux can present as asthma, although this usually isn't considered unless the asthma is relatively severe.

Q. springinstep: Another weaning question, daughter (now six) is anaphylactic to cow's milk - the last reaction was severe (adrenaline, fluids, steroids, salbutamol - the works) and she has probable allergies to sesame, egg and some tree nuts. She also has asthma and had eczema as a baby.

We are now weaning our six-month-old who has been exclusively breastfed up to now. I have been avoiding dairy and egg whilst feeding her and she has no eczema (a small patch on her ankle that might become eczema but nothing like my elder daughter).

Do you feel there is an optimum 'window of opportunity' for introducing allergens? Should we be weaning slowly or be more confident that she seems less atopic than our older child? It feels odd to give her yoghurt in the near future given our history - should we wait until a year or is that likely to make things worse?

A. AndrewClark: When you're introducing new foods such as cow's milk or egg, it is good to provide a baked version first, eg cake in small amounts and build this up as tolerated. Start off by rubbing a small amount against the gum and wait 24 hours, if no reaction give a pea-sized amount and wait 24 hours, and so on.

Other foods such as yoghurt, cheese or milk should wait until heated products are tolerated. Now six months has passed you should be able to introduce these foods, carefully.

Q. Cardamomginger: I have a diagnosed severe multiple nut allergy (worst offenders are almonds and peanuts) and am currently 17.5 weeks pregnant with my first child. Obviously, I continue to avoid all nuts and carry my EpiPen with me at all times. I am keen that my child will be able to eat nuts and will not have a restricted diet.

However, I am also concerned that due to my own diagnosis, there is an increased risk that she/he will be nut allergic. Should I introduce nut products in the diet once he/she is weaned? At what age is best? Is there a "controlled" way in which I should do this? 

A. AndrewClark: There is a slight increased risk of nut allergy in your child, but overall the risk is small. We would follow the Food Standards Agency advice to not introduce nuts into your child's diet before the age of three years, and do so then after discussion with your GP. Often an allergy test beforehand can be reassuring.

Reintroducing foods

AndrewClark: There were questions by sporadicname, Babbit, ggirl, lenga01, Skimty, Squiz, needsdirection, bruffin, tatt, Krispy20, Jammygal, ronshar, QwertyQueen and jamhappi about reintroduction of foods in children with previously diagnosed food allergy.

For peanut and nut allergy, we expect these allergies to be long-lived. Children should be monitored over many years with repeat allergy tests. Generally if these tests become negative then a hospital-based challenge could be arranged, although complete resolution of the allergy is an unusual outcome. More often the tests stay positive, and usually we advise continued avoidance, don't be tempted to reintroduce nuts at home.

For egg allergy, where the worst reaction was mild and where there is no ongoing asthma, we do advocate early reintroduction of egg as children grow out of this allergy fairly rapidly. Broadly, children should be able to tolerate baked egg products (eg cake) by three to four years and uncooked egg (eg mayonnaise) by about six to seven years. However, there is wide variation in the acquisition of tolerance and if there has been a severe reaction (eg with breathing difficulty) then the allergy may be very long lived.

Be guided by your allergy doctor, but generally we would introduce baked egg first followed by lightly cooked egg. We have recently written guidelines for egg allergy management which will be available on the BSACI website before the end of the year (http://www.bsaci.org/index.php?option=com_content&task=view&id=117&Itemid=139). These include a patient advice sheet including home guidance for egg reintroduction and lots of helpful advice for your doctor (including vaccination advice).

Q. sporadicname: My daughter had an reaction to egg when she first had a small spoonful of scrambled eggs at about 10 months resulting in an itchy nettle type rash instantly across the mouth area. She has since eaten egg cooked in things like cakes with no reaction. She is now nearly three, should I be trying her again with egg in forms such as scrambled?

She has had two other reactions to foods resulting in welts across the body and once with slightly swollen lips. GP was uninterested and said that they can't do tests for food allergies. So I am not sure how to proceed.

A. AndrewClark: I can't really answer this question with the information you have provided, and I would need to ask you some questions and do testing. I suggest that you ask your GP for a referral to an allergist as they are unable to answer the question themselves. It is possible to test for food allergy at any age, please do not be put off.

Q. ggirl: I brought my son and daughter to Cambridge for your STAR study about three years ago. We were very pleased that our son could have eggs after the food challenge with a cupcake and now he frequently enjoys pancakes for breakfast - so thanks. He has had a few slight reactions to some things with eggs though. Some homemade brownies that had loads of eggs in them made his lips swell and throat itch. Can the sheer amount of the allergen change the reaction?

A. AndrewClark: Thanks, for everyone's benefit the STAR study followed up about 100 kids with repeat annual challenge, blood and skin tests as they (mostly) grew out of their egg allergy. We did find that everyone resolves along their own 'curve' - some taking longer than others and all resolving to baked before uncooked egg.

It is possible at the terminal stages of resolution to have a high threshold, so that a small amount of egg is tolerated, but a larger amount causes a reaction, this tendency to react should settle in time, although it could take many months.

Q. CantSleepWontSleep: My son ate (homemade) seafood risotto when he was around nine months old (having already eaten prawns without problem before then) and the roof of his mouth swelled massively and remained swollen for two to three hours.

Since then (he is now 18 months) we have not given him seafood again, except for prawns (which our GP advised we should do). The risotto also contained scallops, mussels and a little squid, together with fish stock from a stock cube.

My GP's simplistic approach to this is to say 'just don't give him seafood'. He has not referred him to anyone, but has given some steroids for us to administer in the event of another reaction.

My concern is that if he starts nursery in a few months time he may accidentally come into contact with seafood (parents provide packed lunches) and any action taken by the nursery might be too late. Is there a better approach than the one offered by my GP, and if so, what is it?

Should we offer him some seafood sitting in the hospital car park? His sister likes crab sticks but hasn't been allowed to have them since in case he gets hold of them - could we try him with one of these?

(He also has a milk protein intolerance/allergy, but this is less severe than the reaction to seafood, and we are hoping that he will grow out of it like his sister did.)

A. AndrewClark: I am concerned from two aspects, firstly that your emergency medication seems to be inadequate. We would routinely recommend an adrenaline autoinjector for a child who experienced swelling in the airway (roof of mouth included).

Secondly, you have not really had defined with testing what your child is allergic to. The other aspects which would come with an allergy clinic appointment are also apparently missing (a written emergency treatment plan and education and training of the nursery and later school in adrenaline indications and use). Do not do your own challenge! Seek the advice of an allergist (BSACI.org)

Q. lenga01: My daughter who is now four years old has a nut allergy, but has yet to have an allergy test or any confirmation. I have been referred countless times through my GP and via emergency hospital visits but still no tests. 

We have been treating her by avoiding all nuts and nut traces as it seems like she is very allergic (she once licked a dairy milk bar and had a very severe reaction). The problem is now that she is starting school in Sept and she is having reactions to other foods and I am getting concerned that if we don't know 100% what she is allergic to that she may have a reaction at school.

Is there anything I can do to get a reliable allergy test that will tell us exactly what she is allergic to and would we be prescribed with any emergency medicines (such as an epipen?) I am also 18 weeks pregnant and am very concerned about whether or not I should be eating nuts? I have been told to both eat them and avoid them, so I don't know what I should be doing.

A. AndrewClark: Allergy tests don't work 'blindly' - that is, you should have a good idea from the history of what food you suspect and use the test to confirm that, rather than trawling for a suspect with the test. You should probably see an allergist. There is no evidence to say that moderate nut ingestion in pregnancy is harmful.


Vaccinations and allergies

Q. Calypsoblue: My son has egg allergy. Is this potentially a problem for him when receiving his vaccinations as I understand that some of them are cultured in egg protein.

A. AndrewClark: The latest guidelines for MMR vaccination and egg allergy should provide reassurance. All children with egg allergy should receive the vaccine. Only those with a previous anaphylactic reaction to the vaccine itself should receive the next vaccine in hospital (guidelines can be found in the egg allergy patients info leaflet on BSACI.org). All others (ie including those with severe reactions to egg) can receive their vaccine at their GP's surgery.

Influenza and yellow fever vaccines contain detectable levels of egg protein and present a greater risk. Therefore, if either of these two vaccines are required an allergist should be consulted. 

Last updated: over 1 year ago