Live webchat with Dr Adam Fox

Adam foxThis is an edited transcript of a live webchat with consultant paediatric allergist Dr Adam Fox on 18 November 2008.


Nut allergy | Allergy tests | Intolerance vs allergy | Dairy allergy | Breastfeeding, weaning and allergy | Avoidance diets and nutrition | Asthma | Eczema | Egg allergy | Gluten-free/ coeliac disease | Anaphylaxis | Seafood allergy | Allergic rhinitis | Densensitisation | Oral allergy syndrome | Lymphatic malformation

DrAdamFox: Hi, thanks very much to Mumsnet for inviting me along - I regularly get mums in clinic telling me about what they have read on the site, so it's great to be involved. I will try my best to answer as many questions as I can.

Nut allergy

Q. Lulumama: My son, nine, has a peanut allergy, diagnosed at aged two. I have been told he can be tested further around the age of 10 to see if he has grown out of it. My daughter, three, had peanut butter by accident at a friend's house, random piece of toast on conservatory floor, inquisitive toddler puts everything in mouth, cue me and my friend, who luckily is a nurse, rinsing her mouth out and phone in hand ready for 999. No reaction. So do I presume she is not allergic, or was she lucky that time? Am not prepared to give either child nuts of any type again unless it is in A&E with a paed present with an epipen in each hand.

A. DrAdamFox: Only 7% of younger siblings of nut allergics are also nut allergic so, together with the recent experience, things are looking good for your youngest. I think both your kids need referral to the allergy clinic at your local hospital for skin testing: to skin test your eldest to see if they are one of the lucky 20% to outgrow and your youngest as if the skin test is negative, it makes nut allergy very, very unlikely. In my clinic, when we get the negative result I get the child to eat some peanut butter there and then to reassure the parent.

Q. tealady: I have an 11-year-old son with peanut allergy. Is there much chance of him growing out of it and how often do you recommend retesting? 

"About 20% of children outgrow peanut allergy but most have done so by 11."

A. DrAdamFox: About 20% of children outgrow peanut allergy but most have done so by 11, so I am afraid the chances are slim now. Kids with just peanut allergy, small allergy test at diagnosis and few other allergy problems are the most likely to outgrow.

Q. savoycabbage: My five-year-old daughter has a peanut allergy. We have been avoiding products containing traces of peanuts on advice of our consultant. Is this still the right thing to do? I find the probiotic situation confusing as there are so many different strains. Is there a type of probiotic we could be giving her which may better than others? Should you avoid nuts when you are pregnant?

A. DrAdamFox: The 'traces of nuts' issue is a very individual thing and depends on lots of factors. For some families, where the kids have had very severe reactions or reaction to very small amounts, only complete avoidance will do. However, this is not the same for everyone.

It is important to appreciate what the labels mean as they are over misinterpreted. 'May contain traces' foods usually are nut free but there is a small chance they may contain significant amounts of nut - enough to cause a reaction. Some mums tell me their kids can't be that allergic because they eat the 'may contain' foods and are OK. Of course this is giving them a false sense of security as in fact they have simply been tolerating food with no nuts in at all.

For most nut-allergic kids we support a risk-assessment approach ie if the child is well, supervised and with their emergency medication available, then it would be reasonable to have 'may contain' foods. However, if they are not well ie bit wheezy, in a strange environment, unsure where their Piriton is, then it would be best to play it completely safe.

Q. mmelindt: My daughter is six years old and has an undiagnosed nut allergy (ie has not been tested for the allergy, just what we have observed at home). Her reaction is not as severe as some children, she gets a skin rash that can be very uncomfortable but not life threatening. At present, we avoid all nuts, and have not had her tested as it seems to be an uncomfortable procedure, just to have our theory justified. We know it is nuts that she is allergic to through our observations. Would you advise having her tested? At the moment we do allow her on occasion to have something with the odd nut in it. Should we avoid this in future? If she eats something with traces of nuts (even if a very low concentration) is she more likely to develop a more serious allergy?

A. DrAdamFox: Please get her tested or you are guessing and possibly taking risks trying other nuts. A recent tudy showed allergists got the diagnosis wrong regularly if they didn't back up the history with tests. You also need to look for other related allergies eg sesame in 25% of peanut allergics etc, as well as have somebody take you though managing an allergic reaction, possibly with adrenaline injectors.

Q. KatyMac: As a childminder with a 60ft walnut tree in my back garden, how worried should I be about undiagnosed nut allergies in children? Also we are advised not to feed a child any of the below foods first (ie the parent should): egg, shellfish, strawberries, kiwi. Are there any others we should avoid? or is this advice ill thought out?

A. DrAdamFox: No, I wouldn't worry – obviously let potential customers know it's there but if kids are wondering around your garden putting things in their mouths, I would be more worried about choking than undiagnosed nut allergies. The list of foods is also a bit bizarre, especially as strawberries are a very rare cause of allergy.

Reactions can occur the second or third time you eat the food, so the advice seems a bit silly. It would be far better if you know how to manage a reaction were it to occur and are thus covered for any eventuality.



Allergy tests

Q. rootie2: What is he difference between skin prick tests and RAST testing. Is one better than the other, or one more specific and the other general? What age can they be done?

A. DrAdamFox: Both types of allergy test tell you broadly the same thing. I prefer skin tests in my clinic as I get the result there and then, so can discuss the results and treatment immediately. The downside is you need to have come off antihstamines which some patients haven't in which case we do specific IgE tests (previously known as RAST) but have to wait a few days for the results. However, if skin tests aren't available or give unexpected results, then we use SpIgE.

Q. hellish: How useful are RAST tests? Should we continue avoiding 'may contain traces of...' products (six year old anaphylactic reaction to peanuts)? Have you any ideas on how to deal with extreme anxiety in children who suffer life-threatening allergies? What do you think of 'challenge' type programmes to lesson the degree of allergy?

A. DrAdamFox: RAST tests (now called Specific IgE tests) are really useful for diagnosing immediate allergies (although unlike skin tests, you have to wait a few days for the results). They have to be interpreted with care in the context of the clinical history, otherwise they can lead to over-diagnosis of allergies that aren't really there. Unfortunately, they are of very limited value for delayed allergies.

Anxiety though is a big problem for some families (but surprisingly not for other families). Different things help for different families but spending time with other families in the same situation who have found good ways to cope can really help.

The Anaphylaxis Campaign runs excellent days for kids and teenagers, which really help show how food allergies should not be a barrier to living a normal life. Sometimes, a psychologist can help work through issues, too.

As for the 'challenge' programmes, I know these are offered in some alternative clinics but please be careful as they can be dangerous. There are ongoing trials looking at desensitisation but this has to be very closely monitored and hopefully may prove to be a useful technique – it is still early days, so please don't try this at home.

Q. mamado: My daughter has just turned two and has a peanut allergy (among others) which we know about through testing - she has never had a reaction. After months of suffering from severe ezcema we think that she is also allergic to peas (hope to get her tested on the next visit). Would you say someone with both peanut and pea allergy are at particular risk of having a bad reaction? Also, she was first tested at six months. Her milk reaction was particularly large. At our next visit to the clinic she had such a small reaction that we were booked in for a milk challenge. However, the skin prick test at the start of challenge was again quite large so the challenge did not take place. Do you have any explanation for this?

"The size of the wheal (bump) on the skin test, or the number that comes back on the blood test, does not, in any way, relate to the likely severity of an allergic reaction."

A. DrAdamFox: This is a really important question. The size of the wheal (bump) on the skin test, or the number that comes back on the blood test, does not, in any way, relate to the likely severity of a reaction. It relates to the likelihood that the child is actually allergic. The high number doesn't imply that you will have an anaphylaxis any more that a low one doesn't mean they will only get a mild itch. You child still has milk allergy (as evidenced by the large skin test) but when it started to fall in size, it just suggested tolerance may be developing (wich turned out not to be the case). Pea reactions are uncommon but most commonly in peanut allergics (they are both legumes). There is no implications in terms of having worse reactions.



Intolerance vs allergy

Q. VeniVidiVickiQV: Could you explain the difference between an intolerance and an allergy. There seems to be quite a bit of confusion about it.

Also, I wondered what your opinion/experience of the links with asthma, eczma and allergies were - particularly in reference to cow's milk protein? My daughter was born with cow's milk protein allergy and has also had eczema from birth (was breastfed for seven months then went on to soya formula milk). She developed asthma suddenly at one year of age, and she is considered 'atopic'. She had an epipen because it has shown she is allergic to peanuts through blood tests.

Lastly, what is your experience, knowledge of breastfeeding vs formula feeding in terms of allergy risks in infancy through to teenage years and adulthood?

A. DrAdamFox: An allergy is a reproducible reaction that involves the immune system. This may be immediate eg like peanut allergies, or delayed (most commonly to milk and soya in infants - unfortunately this was often called 'milk intolerance' in the past).

Reproducible reactions that don't involve the immune system are called intolerances eg lactose intolerance. These are a completely different entity but unfortunately many places (including some newspapers who should know better) use the terms interchangeably and cause lots of confusion.

Q. VeniVidiVickiQV: Thank you! So, what is or causes an intolerance if it isn't driven by the immune system?

A. DrAdamFox: Most common is enzyme deficiency eg lactose intolerabce due to losing the enzyme to break down lactose (as most people do).

Dairy allergy

Q. littleted: My five-year-old son has a very 'spotty' face - a bit like goosebumps/small spots, particularly on his cheeks. His forehead and chin are OK. I wondered if this may be due to an allergy? The rest of the skin on his body is nice and smooth and normal. I wondered if it may be cow's milk allergy (as intolerant of this when a baby) but don't want to cut it out his diet. Do you think I should see a local doctor maybe. In good health otherwise, just looks very unsightly. 

A. DrAdamFox: It's possible but unlikely and a food allergy is, to be honest, very unlikely. However, as you suspect, you need a doctor to have a good look at the rash to make a diagnosis – I would go for your GP followed by a dermatologist if required, rather than an allergist.

Q. crybabybunting: I have a high sensitivity to dairy products, which caused me to sneeze constantly and feel very congested until I elimiated them from my diet about 10 years ago. I haven't been able to reintroduce cow's milk products although I am OK with sheep and goats' cheese, milk etc.

My daughter (11 months) has had a runny nose her whole life and constantly has her mouth open. The only time her nose was clear was after she had a tummy bug where she didn't keep anything down for a few days. I'm thinking about switching her to a dairy-free formula and completely cutting out dairy to see if it makes a difference, but I'm worried about how to make sure she has enough calcium and would appreciate some guidance before I start messing about with her diet. How long should I cut the dairy out for and at what point do I reintroduce it?

A. DrAdamFox: I think somebody certainly needs to look at your baby's airways as it does sound like she has either big adenoids or inflamed nasal lining, which is stopping her breathing through her nose. The association with milk is very controversial and certainly shouldn't be considered until the common causes have been properly considered.

" I really wouldn't go down the route of dietary exclusions for nasal problems as it is profoudly unlikely to be helpful."

I really wouldn't go down the route of dietary exclusions for nasal problems as it is profoundly unlikely to be helpful. If you are determined to do so, go for a complete milk exclusion for two to three weeks and see if the problem goes away but still make sure you reintroduce it to see if things really get worse. If you are strict and do this probably I'd be really surprised if you found an effect (but please let me know if you do).



Breastfeeding/ weaning and allergy

Q. Luluvic: My questions relate to the potential protective effects of breastfeeding with regards to atopy and food allergy. From your research and case experience, is there any evidence to suggest that the longer an infant is breastfed the lower the risk of them becoming atopic or allergic to foods? If yes for food allergy, could this possibly be due to minute food molecules in breastmilk that effectively 'teach' the immune system not to react to them later when the child eats the food? So is there merit in eating as wide a range of foods as possible whilst breastfeeding (inc nuts)? Many thanks

A. DrAdamFox: Allergy prevention has been the subject of lots of research. Pretty much the only thing shown to help is exclusive breastfeeding for four months. Continuing beyond this hasn't really been shown to help prevent allergies (although it may well have other health benefits).

Unfortunately, diet during pregnancy doesn't seem to make any difference either way ie eating no nuts or eating lots of nuts.

Q. VeniVidiVickiQV: Does age of weaning show any trends with regard to allergies? What would your advice be to parents of children with proven allergies, or all parents generally?

A. DrAdamFox: The best age to wean is currently of great research interest and a big study at St Thomas' Hospital is about to start, looking specifically at this. The theory is that early weaning may well help prevent food allergy but this needs to be looked at in a study. Current best evidence suggests exclusive breast feeding up to four months protects against allergic disease. Of course, prevention of allergic disease is not the only reason to breastfeed and many other benefits have informed the WHO advice to advocate exclusive breastfeeding to six months.

It would, however, be inaccurate to claim that exclusive breast feeding beyond four months has been shown to help prevent allergies. There is also evidence to suggest that early introduction of solids (prior to 17 weeks) is associated with higher risk of allergies but this is not based on cast iron data, just the best available. 

"There is mounting evidence that early oral exposure (ie <17 weeks) to allergenic food proteins may actually help to prevent food allergy."

There is mounting evidence that early oral exposure (ie <17weeks) to allergenic food proteins may actually help prevent food allergy. In order to get to the truth, an interventional study is needed, which is what I was alluding to. The study will compare those who introduce solids from three months to those who delay introduction to see the effect on development of food allergy. This will hopefully shed more light on what the best weaning advice should be.

I hope this clarifies things a little, but weaning and its impact on allergic disease is a difficult area and we know very little for definite. However, even exclusive breastfeeding doesn't by any means prevent all allergic disease - you can't change your genes, and at best can only hope to shift the odds slightly more in favour of less allergies.



Avoidance diets and nutrition

Q. MeMySonAndI: Hello, my son (five years old) has a considerable number of allergies diagnosed: peanut, egg, wheat, almond, hazelnut, shrimps, house dust mite, grass, dairy, soya, fish (excepting white fish), kiwi and bananas. He is also intolerant to other meats, fruits and vegetables. All these allergies have been diagnosed by RASTs, and corroborated by skin prick tests.

He carries an epipen, and has been in a restricted diet for three years. His yearly reviews show that he is developing more allergies than he is outgrowing. Is there anything that could be done for him other than avoidance of the allergens? I worry there may come the day when it will be imposible to keep his nutitrion up to a good standard. He already seems quite small and thin for his age. Many thanks

A. DrAdamFox: Unfortunately, for the moment, avoidance is the mainstay of treatment although hopefully things will change. A couple of things spring to mind – it is unusual (but not impossible) to be truly allergic to so many foods as you are describing. What worries me is that it sounds like the diagnoses are all based on allergy tests (skin prick and blood tests). These tests are sometimes overinterpreted and every positive test considered to represent a true allergy leading to avoidance.

A low-positive test often doesn't mean you are really allergic and the tests MUST be interpreted together with a detailed clinical history. I see loads of kids avoiding foods unnecessarily because of this and I would encourage you to ensure your son is assessed by a doctor experienced at managing multiple food allergy (apologies if you are already).

Also, it is essential to get advice from a paediatric dietician as even in multiple food allergy, with good advice a complete, nutritious diet can be obtained (albeit with a lot of hard work).



Allergic asthma

Q. cmotdibbler: My 2.5-year-old son has had a cough and wheeze since he was six months old. He has had recurrent chest infections since, and is now on inhaled steroids and salbutamol to try to control the cough/wheeze. He is OK-ish in the summer, but then gets bad each winter (we can always hear his breathing, to the extent that you can track where he is in the house).

Although his breathing can get distressed, he never has what I would think of as an acute asthma attack with massive wheezing, it's more like his lungs get filled with mucus (and he has had a lobular collapse due to mucus plugging). He has had skin prick tests for common inhaled allergens, all of which were negative.

I have a strong family history of allergy, and have coeliac disease, asthma and eczema myself. Is it worth pursuing further allergy testing for my son, or is this not a typical picture of allergic asthma in toddlers?

"Respiratory allergies develop over childhood, in contrast to food allergies that predominate in early life."

A. DrAdamFox: Not all asthma/wheeze is related to allergy but negative allergy test early in live doesn't rule out a possible role. Respiratory allergies develop over childhood (in contrast to food allergies that predominate in early life) and so if things aren't better then testing again at some point may reveal something useful.



Allergic eczema

Q. bythepowerofgreyskull: Do you believe diet has alot to do with eczema?

A. DrAdamFox: This is a fascinating area that I spend a lot of time on - 75% of mums with kids with eczema manipulate the child's diet. Many dermatologists dismiss the role of food in eczema while some allergists probably overstate the potential to improve eczema with diet. The truth is probably between the two.

In kids with severe eczema that starts in the first few months of life there is the most chance that dietary change guided by allergy tests and an experienced clinician can make a difference, which can sometimes be quite profound. However, in older kids with milder onset that started after infancy, there is very little role for diet.



Egg allergy

Q. flowerbud: My two-year-old daughter has a severe reaction to egg, established from a skin prick test at six months old due to severe eczema (she has never eaten egg). We were advised she could be anaphylactic. Egg challenges in hospital have failed as she would not eat the cake containing egg. I have been refused an epipen. Can I insist on having one, considering the advice I have been given? Sorry, forgot to add, she has had subsequent skin prick tests 6mthly and the reaction is still as bad.

A. DrAdamFox: Anyone with an immediate type food allergy (which is what you are describing here) could potentially have an anaphylactic (ie life-threatening) reaction but these are very uncommon in egg allergy.

There is a lot of debate about which kids should have epipens prescribed, although some consensus is emerging following the publication of a 'position paper' from the European Academy of Allergy.

Generally, Epipens or Anapens are given to kids who have both a food allergy plus a history of asthma (a major risk factor for having severe reactions) or food allergy that has caused a severe reaction in the past. Personally, I think prescribing an Epipen is an individual decision to be made by the parent and family together. While I would always give one to anyone with either of the above criteria, other factors may also influence the decision ie what the child is allergic too (nuts are more likely to cause bad reactions), distance from medical care, age of child (teenagers are most at risk of severe reactions) plus anxiety ie if the parents can't sleep for worrying that they don't have epipens, then it makes sense to prescribe them. However, this needs to be combined with a discussion about the real risks of severe reactions, which are fortunately uncommon.

Of course, if you do get an epipen it is essential that you are shown properly how to use it. Just to mention that it is very common for two year olds to struggle to eat enough egg for the food challenge and things often don't get resolved until they are three.

Q. bythepowerofgreyskull: My two-year-old son is a fussy eater but when he eats eggs, which he enjoys, he has no problems with his digestive system but he gets hives if the egg touches the outside of his mouth (only on the area where the egg touches). SHould I stop giving him eggs or is this nothing to worry about?

A. DrAdamFox: Egg allergy is really common (approx 2% of kids) but you are correct that this doesn't sound like this. A fair number of kids, often those with eczema, get redness around their mouths but are absolutely fine when they eat the food. It sounds like this is the case and I agree you shouldn't cut eggs out of his diet - life is hard enough with a fussy eater!



Gluten-free/coeliac disease

Q. thesockmonsterofdoom: My five year old has all the symptoms of coeliac disease, and has no symptoms when she does not comsume any gluten. The symptoms return immediately if gluten is consumed. She had a blood test for coeliac, which was negative, and is not having any further tests. Is it possible to have coeliac disease but test negative for it, or could she just have a severe gluten intolerance?

A. DrAdamFox: Diagnosing coeliac disease is very tricky without gluten in the diet for approximately three months, as the screening tests will be negative as there is no inflammation to detect. This is hard as you don't want to make your child sick by putting them on gluten. However, some kids can get a transient gluten hypersensitivity that they may outgrow, so at approx 7-8 years it is important to confirm the diagnosis of coeliac disease before committing to a lifelong diagnosis.

Obviously, if attempting to reintroduce gluten makes them sick, you probably have your answer, but if you were able to persevere to get the TTG blood test or even better an endoscopy and biopsy (the gold standard test) then that is the ideal.

Q. sockmonster: We tried gluten in a very tiny amount for two weeks and she was so ill and badly behaved and tired again. Am very scared to try for any longer for the tests.

A. DrAdamFox: I would leave it for a couple of years and then ask for a referral to a paediatric gastroenterologist. Ideally, try the gluten again 12 weeeks in advance of the appointment (otherwise that is what they will tell you to do).

Q. silverfrog: I have two daughters - my elder daughter (aged four) is autistic, and has benefited from a gluten and dairy free diet (Sunderland protocol). I have kept my younger daughter (now 21 months old) largely (99%) gluten and dairy free, as advised when trying to avoid autism triggers. I suspect my elder daughter may have a corn intolerance, too. How might I go about finding out if this is the case? I am reluctant to fiddle around with her diet too much, as she is a very fussy eater.

My younger daughter rarely produces formed stools. She has not been tested for coeliac, as she is already gluten free. Her current paediatrician (she is FTT, and weighs 18lb at 21 months) dismisses my concerns as 'toddler diarrhoea'. I think this is too simplistic. How can I go about finding out what might be irritating her bowels? On a Bristol Stool Scale rating, her stools are type 7 95% of the time. Something must be wrong, but no-one will take me seriously. What can I do?

A. DrAdamFox: Sorry to hear about the difficulties you're having. Most families of kids with autism get a pretty crappy deal from the health services. Regarding your eldest, there are (as I suspect you know) no decent tests for these sorts of intolerances so your only option is an exclusion diet followed by reintroduction to see what effect it has. As your daughter is already on multiple exclusions you have to be really careful here as you could cause real nutritional compromise. The answer is a carefully supervised exclusion done together with a paediatric dietician for say four to six weeks. Your GP will be able to refer you to one but even better if there is one attached to the community paeds who see her about her autism.

The important thing is to keep an open mind and even if it seems to help, make sure you still reintroduce the corn to see if it makes things worse again. If you don't see a clear effect on exclusion, reintroduction and again on further exclusion, it is very unlikely the food is really playing a role. I see so many kids who have had a food excluded, no clear difference was seen but they were just kept off the food anyway.

Regarding your youngest, it is hard to comment but the persistent loose stools are a worry. I would suggest you discuss your concerns with your paediatrician and ask them about other possible diagnoses that were considered and how the conclusions were reached. If you are not happy you could ask your GP for referral to a paediatric gastroenterologist.



Anaphylaxis

Q. athomeagain: Our three-year-old daughter has been diagnosed for well over a year as anaphylactic to eggs, peanuts, walnuts and sesame. Her latest skin prick test showed level 5 reactions (the same as the control). She has also reacted to items in the park that people have been eating on and to people touching peanuts and then her. At the moment we are being extra cautious with absolutely everything that she touches and we are not eating anything that cannot be assured to be safe.

Do you have any suggestions as to what we should be doing? We have read a piece of research that says that if we were to eat, drink and clean our teeth after eating something with an allergen in it then we would be unlikely to contaminate her with that allergen. We are also concerned by ingredients in things that she might use rather than eat (eg paint, playdoh) or in products that we might use (eg shampoo or body lotion and especially anything that may linger on the skin) and we tend to shy away from letting her use things until we have confirmed that they are safe or checked the labels. Do you have any suggestions in this regard?

How likely are children to cross-contaminate each other? Do you have any suggestions as to how we should deal with the nursery? At the moment all our specialist has told us is that we need to be 'sensible' in our approach. We are finding that simple word quite difficult to put into practice as 'sensible' seems to us to be to make as sure as we can that she does not come into contact with the allergens and therefore avoids another reaction.

Overall our lives are ruled by places where no one is eating or face-painting, playing with dogs, using animal foods etc and this is affecting the whole household. Do all of the things she is allergic to sustain the same amount of risk ie if someone were to eat a sandwich containing mayonnaise next to her and then hold her hand is this a real risk? We ask as we have moved her away from children in the park because of situations just like this.

We have recently been told that she will only have an anaphylactic reaction if she ingests the food that she is allergic to and not if she touches it. Is that right? What will destroy the proteins for nuts and eggs? Is soap and water enough? So, if she touches a food that might contain her allergen if she then washes her hands will that prevent her ingesting even traces of it and thereby prevent an anaphylactic reaction? With thanks and confusion!

A. DrAdamFox: I would really recommend you ask for a referral to an allergy clinic, as I am a bit worried about the advice you have been given. Food allergy should not have this sort of impact on your life. We simply do not see nasty reactions to casual contact, only really through eating the allergen.

A nice American study shown only 30% of patients with severe peanut allergy reacted even to a patch or peanut butter stuck to their skin and even then only had mild skin reactions. Please also ask to see a paediatric dietician (should be available in the allergy clinic).



Seafood allergy

Q. twocutedarlings: Twelve months ago my daughter (just four years old) had an allergic reaction to what we believe was prawns. Her face swelled like a balloon (she couldn't even open her eyes) and her body (mainly around her joints) was covered in hives. Thankfully, it didnt effect her breathing and after a manic trip to A&E we were sent home with piriton and all has been fine since.

The doctor we saw at A&E advised us to give her a couple of months to recover and to give her prawns again to see if she reacted again hmm. Rightly or wrongly, I chose not to take his advice a we have avoided all shellfish ever since. I realise that it is important to find out for definite, so what would your advice be? Should I go our GP and ask for her to referred for test or should we give her prawns and see?

A. DrAdamFox: I definitely agree with your decision, it is very likely there would be another reaction and possibly a more severe one. Testing would confirm the diagnosis and also allow you to look for allergies to molluscs (rather than just crustaceans) and other common allergens they may not have eaten yet eg nuts hence avoiding reacions.



Allergic rhinitis

Q. 10krunner: My eight-year-old son for the past four years has trouble breathing through his nose. He snores terribly and is forever having to blow his nose because it was running. He saw an ENT specialist who confirmed the lining of his nose was thickened and he had a deviated septum (as had I until an operation). In May this year he had an operation to thin out the lining of his nose and had his adenoids removed, which were very swollen and he briefly had some relief from his symptoms. But they've all now come back and it's as if he never had the op.

He was subsequently prescribed ceterizine to take 2x5ml at night before bed and this has also made no difference.

We've done all the allergy stuff in his room ie hoover, damp dust, mattress protector, removed the carpet but it has also made no difference. Any ideas on the back of a postcard, please. I meant to say, he had some blood tests done which showed he was very allergic to dust and grass.

A. DrAdamFox: This does sound like allergic rhinitis. Two other medicines may well help - a nasal spray such as Nasonex and an anti-inflammatory called Singulair. Allergen avoidance is hard work but check out the Indoor Biotechnology website. They can send you a home testing kit to see the levels of dust mite in, most importantly, the bedroom and can then help advise on reducing levels. If all this doesn't work then desensitisation may help - you will need to be seen in a specialist allergy service for this though.

Q. ukrainianmum: My daughter has been caughing for over two months now. And recently she developed this stange habit like clearing the throat. Not coughing itself but this very particular sound like she is irritated in her throat. Her lungs, throat and everything are clear, blood and urine tests all good. Could it be the sign of any allergy? thank you. 

A. DrAdamFox: Has somebody looked up the nose? This is the most likely place to be causing problems - an allergic rhinitis would give these symptoms.



Densensitisation

Q. ladyjuliafish: What are your thoughts on the desensitisation study at Addenbrooke's Hospital and the Chinese medicine study at Johns Hopkins/Mount Sinai?

A. DrAdamFox: These are two exciting projects (Addenbrooke's have a study looking at desensitising kids with peanut allergy and Mt Sinai are looking at allergy prevention and treatment using a Chinese herbal formula) and I strongly suspect that desensitisation will soon become a real option in food allergy, although trials are still in the early stage.

It is essential that the desensitisation is shown to be safe before it is rolled out and, thus, far bigger studies (which take time) will be required plus also evidence as to whether children are being desensitised (and will react again once the daily peanut dose is stopped) or if there is true tolerance induction (ie they remain allergy free once they stop daily peanut) – this will take time.

As for the Chinese herbal formulae – most work has been on mice and, to be honest, until the active ingredient is clearly identified it won't get licensed for widespread use in kids. Young kids with peanut allergy have a 20% chance of outgrowing the allergy – this is higher if they have few other allergic problems and higher still if their initial allergy test was small (yours was middling).

Unfortunately, there is no suggestion that probiotics (or currently anything else for that matter) would help. What you do during pregnancy (ie avoid nuts or not) has never been shown to make any difference.

Q. Tatt: Do you think desensitisation will work on adults? My teenager has severe nut allergy - how likely is it that desensitisation programmes will be established at locations other than Cambridge? I've read that dehydration increases histamine levels. Do you think this could be a factor in exercise induced anaphylaxis? Anecdotally, anaphylactic reactions on planes are more severe - any research on this? Again could dehydration be a factor?

Paediatricians argue that consultant allergists are unnecessary and can even be harmful. My experience of both paediatrician and consultant allergist is that the latter is far better informed and hence more helpful. What's your view / how can the number of allergy specialists be increased? How do we train GPs better?

A. DrAdamFox: I have never heard peadiatricians arguing against the need for allergists (although may be they stop saying it when I am around). I would argue that the best people to manage children's allergies are paediatric allergists (but I would, wouldn't I?). GP training in allergies is getting better all the time, thankfully.

Q. cariboo: Is it possible, and safe, to desensitise an adult peanut allergy sufferer? 

A. DrAdamFox: Lots of people are asking about desensitising and it is a really hot topic for allergists. The idea is to change the underlying immune response to an allergen by exposing the allergic person to lots of it either by injections or squirted under the tongue. It works really well for pollens eg in hayfever but is still very experimental in foods and only should be done as part of a clinical trial.

Results look promising in some studies but it is a fair way off being widely available. Injection immunotherapy to nuts is most definitely dangerous and definitely a bad idea.



Oral allergy syndrome

Q. IdLikeToBeDelilah: My 12-year-old son occasionally gets a large swelling lip after eating an apple (he uses this as a good excuse not to eat them!) and sometimes complains of mouth/lip tingling with other fresh fruits such as tomatoes. He's also had a couple of major lip swellings after eating red-coloured ice lollies. I read recently that allergies giving rise to this type of reaction in the mouth should be investigated because of the risk of more serious reactions in the throat. Would be grateful for your thoughts on that.

"Oral Allergy Syndrome usually happens in kids with hayfever. Severe reactions are very, very rare."

A. DrAdamFox: This sounds very much like Oral Allergy Syndrome, a cross-reaction with pollen. It usually happens in kids with hayfever, who have previously eaten the food such as apples without problems but then find they get the symptoms you have described. They can tolerated cooked or processed apples eg apple pie and apple juice in cartons and often peeled apples. Severe reactions are very, very rare but other foods may be affected. However, your child needs to see an experienced doctor to get the whole story and confirm the diagnosis with allergy tests.



Lymphatic malformation

Q. Rootie2: Please could you tell me if you think there is a relationship between the lymphatic system and allergies. I'm desperate for help with my one year old who had a lymphatic malformation in his mesentery (abdomen). Half was removed a month ago, but he still is very rashy at times and has loose stools up to six times a day. Could he have developed a lactose intolerance, could a blockage to the lympahtic system cause immune/allergy issues? Please help!

A. DrAdamFox: I don't think the lymphatic malformation is relevant here but that doesn't mean your son doesn't have allergies. I actually think the most likely problem in intermittent urticaria - where kids just come out in hives for no particular reason. This is often put down to foods but, of course, the relationship proves inconsistent as you have mentioned.

This does need a paediatrician/allergist to check out, but usually responds extremely well to simple antihistmaines such as a decent dose of cetirizine (piriton is not great for this condition as it is short acting and sedating).

DrAdamFox: Thanks to the Mumsnet team for inviting me along. All the best.

Last updated: 16-Apr-2013 at 2:14 PM