Webchat with consultant paediatric allergist Dr Adam Fox, Tues 18 Nov, 12.45pm

[GeraldineMumsnet]

We're delighted that top children's allergist Dr Adam Fox has agreed to come on to Mumsnet to answer queries about all things allergic. Please post any advance questions here, particularly if you're not able to make it on the day.

[mamado]

Hi Dr Fox,
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 6 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?

Many thanks

[thesockmonsterofdoom]

we tried gluten in a very tiny amount for 2 weeks and she was so ill and badly behaved and tired again. Am very scared to try for any longer for the tests.

[DrAdamFox]

dear greyskull - this is a fascinating area that i spend a lot of time with. 75% of mums with kids with eczema manipulate the childs diet. Many dermatologists dismiss the role of food in eczema whilst some allergists probably over state 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 change 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 v little role for diet

[DrAdamFox]

sock monster- i would leave it for a couple of years and tehn ask for a referral to a paediatric gastroenterologist. Ideally try the gluten again 12 weeeks in advance of the appointment (otherwise that is whtthey will tell you to do)

[VeniVidiVickiQV]

Hi, I have 3 things I want to ask!

Could you explain the difference between an intollerance 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 cows milk protein? My daughter was born with cows milk protein allergy and has also had eczma from birth (was b/fed for 7 months then went on to soya formula milk). She developed asthma suddenly at 1 years 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?

[thesockmonsterofdoom]

thanks

[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?

[VeniVidiVickiQV]

Ah, you appear to have answered my eczma/allergy query

[MmeLindt]

Hello Dr Fox,

my DD is 6yo 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?

Thank you for your time.

[DrAdamFox]

dear mamado - 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

[DrAdamFox]

Dear rootie2 - 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 then. The downside is you need to have come off antihstamines which some patients haven't in which case we do Specific IgE tests (prev 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

[DrAdamFox]

Dear Luluvic ? allergy prevention has been the subject of lots of research. Pretty much the only thing shown to help is exclusive breastfeeding for 4 months. Continuing beyond this hasn?t really been shown to help prevent allergies (although 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.

[bythepowerofgreyskull]

Sorry - me again...

do you think there is a genuine rise in the m=number of children with allergies or is there more awareness of things? or both?

[DrAdamFox]

dear mmelindt - 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% on peanut allergics etc as well as have somebody take you though managing an allergic reaction, possibly with adrenaline injectors.

[VeniVidiVickiQV]

Exclusive as in breastfeeding only (not mixed with formula feeding), and not introducing solids (in the form of baby rice in bottles or otherwise) before 17 weeks?

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?

[Luluvic]

Thanks, interesting about the 4m exclusive bfeeding. What about diet during breastfeeding? or is there not enough research yet?

[VeniVidiVickiQV]

Advice with regard to weaning I mean!

[DrAdamFox]

Dear VVVQV - 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 completelydifferent entity but unfortunately many places (inc some newspapers who should know better) used the terms interchangably and cause lots of confusion

[mamado]

many thanks for your reply Dr Fox. Does that mean I shouldn't worry too much that my daughter's wheal on first testing was 'off the scale' it was so big?

[tealady]

Hi Dr Fox. I have an 11 year son with peanut allergy. Is there much chance of him growing out of it and how often do you recommend re-testing?

Thanks

[DrAdamFox]

VVVVQ - exclusive is as you say. 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. Our current advice is to follow the WHO ie ideally 6 months exclusive but the studies on kids at high risk of allergy show increased problems only if solids are started pre 17 weeks

[twocutedarlings]

Hi there,

12 months ago my daughter (just 4 years old) had and allergic reaction to what we believe was prawns her face swelled like a balloon (she couldnt 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 pieriton and all has been fine since.

The doctor we saw at A&E advised us to give her a couple on 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 shell fish ever since.

I realise that it is important to find out for definate, so what would your advice be? should i go our GP and ask for her to refered for test or should we give her prawns and see ?

[DrAdamFox]

Dear IdLikeToBeDelilah - 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. Check out the excellent Wikipedia article on this. Severe reactions are very, very rare but other foods may be effected. However, your child needs to see an experienced doctor to get the whole story and confirm the diagnosis with allergy tests.

[VeniVidiVickiQV]

Thank you! So, what is or causes an intolerance if it isnt driven by the immune system?

[DrAdamFox]

dear tealady - about 20% 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