Challenge testing

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LMG1663*
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Joined: Mon Apr 14, 2014 9:23 pm
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by LMG1663* on Mon Apr 14, 2014 9:47 pm

Challenge testing

Two of my children have been diagnosed with peanut allergy and carry epipens. My 16-year-old daughter once had a very bad reaction requiring hospitalisation, and both she and my son (now 13), who had also displayed a reaction to peanut butter as a toddler, went for skin-prick testing. My daughter's "lump" was massive, whereas my son's, though indicating a reaction, was much smaller. Since then he has never had any kind of serious reaction - he was sick once after accidentally eating a Snickers from a box of Celebrations, but reckons he's been in the vicinity of peanuts recently (friends eating them next to him) and it hasn't bothered him. I'm wondering if he might be one of he "false positives" we hear about in articles such as thie? http://www.uhsm.nhs.uk/news/Pages/Scien ... tcode.aspx And I also wonder whether the fact that he is the sibling of someone who once had a serious reaction, contributed to his own diagnosis? (I have two other children, but they have never displayed any problems).

Anyway he is now looking to the future and thinking about his career options. He is interested in training as a pilot. Joining the RAF is ruled out as anyone with a food allergy is not allowed to join the armed forces. As for the civilian route, we've heard from the aviation medical department that anyone with such an allergy could train but would not be allowed to fly solo, and there might be problems with employment. So this diagnosis clearly has implications for my son's future career, and with this in mind I have requested an appointment at the food allergy clinic at Northampton General Hospital to discuss the possibility of "challenge" testing. My concern is that NGH is not a center of excellence in this particular field (it's all lumped in with the paediatric department, and they basically pack you off with an epipen and tell you to avoid peanuts, being apparently very closed to any suggestion of possible future desensitization treatment!) and I'm worried that on Wednesday we'll be told "we don't do that here" or words to that effect. My question is, how do I go about confirming that my son's diagnosis really is a correct one? I'm prepared to travel but I just don't know where to start.

On a more general level, for both my son and my daughter, it's really frustrating seeing news reports of people with life-threatening allergies munching their way through a peanut in the name of "research", all quite safely, while my two kids have to remember every single time they go out to take their life-saving epipen with them on the offchance they might eat the wrong thing! Surely the research must be reaching the point where it can be rolled out to everyone with this potentially devastating condition?

Sorry for the long post, but I couldn't pass up on the opportunity of asking specialists about this.

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Dr Helen Brough
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Joined: Wed Feb 16, 2011 3:36 pm
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by Dr Helen Brough on Tue Apr 15, 2014 12:54 pm

Re: Challenge testing

Dear LMG1663,

Thank-you for your comprehensive post and for highlighting two topical issues at the moment: careers and food allergy and peanut desensitisation.

With regards to your son's possible career as a pilot, I do think it is important that you have more clarity on whether he still has peanut allergy or whether he has grown out of his peanut allergy. He should also be checked as to whether he has allergies to tree nuts and sesame seed as these allergies can co-exist in around 40% of peanut allergic children. Thus even if your son has grown out of peanut allergy, he may have tree-nut or seed allergies (unless he is already eating these foods- I could not tell from your post). Approximately 20% of children grow out of their peanut allergy; this is usually assessed by a reduction in peanut skin prick test wheal size and specific IgE tests not only to whole peanut but also to the major allergens in peanut (Ara h 1,2 and 3) followed by a hospital based diagnostic oral food challenge to peanut. I would suggest that if your local hospital is not set up to perform diagnostic food challenges that you asked to be referred to a tertiary specialist paediatric allergy centre of which there are now quite a few.

I now turn to the topic of peanut desensitisation, which was recently in the UK press following the publication of research performed in Addenbrooke's Hospital in Cambridge. http://www.cambridgeallergytherapy.com/ news/cambridge-study-peanut-allergy-therapy-shows-84-cent-success.html. There was also a good review of this at the time on the BBC: http://www.bbc.co.uk/news/health-25917272

Although this research is potentially very exciting and certainly helps towards the body of work in this field I need to stress that this treatment does not cure peanut allergy. We know from other studies looking at food oral desensitization that after stopping regular consumption of the food, in most cases the allergy returns so this treatment does not 'turn off' allergy long-term, it only suppresses the food allergy whilst taking the treatment. Children in the STOP II peanut desensitization study were advised to eat daily doses of 800 mg of peanut protein; they were not told they could eat lots of other peanut containing foods but they did not need to worry about accidental exposure to small amount of peanut in other foods. If these children were allergic to tree nuts then they would have still needed to avoid foods with possible nut contamination.There is work ongoing trying to combine peanut oral desensitisation with other immune modulators to try to 'switch off the allergy'. There is also work ongoing to try to prevent peanut allergy in young children with a high risk of developing peanut allergy in the LEAP study (http://www.leapstudy.co.uk/). These results should be published next year.

Dr Helen Brough
Consultant in Paediatric Allergy
Guy's & St. Thomas' NHS Foundation Trust

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