PeanutAllergyUK

[Storm]

Fewer people have real peanut allergy than previously thought

Scientists have developed a new more accurate test for peanut allergy after finding that eight out of ten children who previously tested positive were not in fact allergic to the nut.

Researchers in Manchester and experts in Sweden have developed a blood test which is much more accurate than current testing methods and have found that peanut allergies have probably been overestimated.

The test only detects antibodies to a very specific part of the peanut which triggers the allergic reactions, which in severe cases can be fatal.

Current tests pick up antibodies to much more of the peanut, most of which are irrelevant to the development of allergies, giving large numbers of false positive results.

Read the rest of the story here: http://tinyurl.com/ybcjrvy

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Peanut allergies less common than tests suggest

NEW YORK (Reuters Health) – Many children who test positive for sensitivity to peanuts may not actually have full-blown allergies to the food, a new study suggests.

UK researchers found that among 79 8-year-olds who were deemed peanut- sensitive by standard allergy testing, only 7 turned out to have true allergies when they underwent more-extensive testing that is less commonly used in routine practice.

As it stands, peanut allergy is typically diagnosed through a skin test, blood test or both.

During skin testing, the skin is pricked and exposed to a small amount of peanut protein to see if there is a reaction; blood tests, meanwhile, help diagnose peanut allergies by measuring levels of IgE antibodies, immune system substances that play an important role in allergic reactions.

Read the rest of the story here: http://news.yahoo.com/s/nm/20100113/hl_nm/us_peanut_allergies
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12-year-old son: allergic to peanuts, nuts and raw egg whites

[beggsie]

That is fantastic - exactly the kind of research that makes my heart swell! I wonder if this will relate to tree nuts? It mentions not other allergies like milk, egg etc, but perhaps tree nuts?

beggsie

[allerG]

Extremely useful these tests are, they have long been available in the research setting but are now commercially available. They assess IgE reactions to a select sample of the proteins that make peanut such a potent allergen.

Their greatest use is in more definitively defining milder intraoral reactions to peanut, which arise due to cross reactivity with grass pollen. This usually comes about in older children and in adulthood. There is often a history of past peanut tolerance. This is known as the Oral Allergy Syndrome, and represents a low health risk, although the symptoms are rather unpleasant. In this example the rAra h 1,2,3 tests are negative, but the cross-reactive rAra 8,9 are positive. Birch pollen and Hazel nut are also a good example of pollen-food cross reactivity. Many of the posts on this forum detail such reactions and you can appreciate how surprised adults are when they develop the OAS.

The use of component tests in classic 'severe' peanut allergy is slightly more challenging as they are not definitive enough to give a child (with low positive Skin Test and/or IgE test, to peanut) the 'all-clear', unless a supervised incremental oral challenge is performed. When the rAra h2 is positive, and indeed when (3+1) or (3+2) combinations do arise we are justified in being more cautious, but are always cautious wrt peanut allergy. So, in the absence of a history of allergy or tolerance to peanut, and with low positive tests, you will still require a safe challenge prior to getting the 'all-clear' and safely being able to drop your guard wrt avoiding peanut.

Component testing is now available to more and more important food (and aero) allergens such as egg, milk, wheat.... It is extremely exciting to be able to further interrogate the immune systems responses to these common food allergens.

[emmaj24]

Thank you George, that's really interesting. A great explanation and indeed is an exciting development.

[aaargh!!]

Thought this was really interesting. My daughter seems to have recently developed oral allergy syndrome to some fruits. She has never actually reacted to a peanut (only a walnut). However, at age 5 her scratch test to peanut showed a significant reaction to peanut so we avoided it. At age 8, her blood test only showed a level 1 allergy to peanut. She has not had any incidents in the last two years, although we are very careful. I often wonder if she is still allergic, or now intolerant or not?

[emmaj24]

Do you think that the PhadiaAB test that the Manchester hospital will be used more widely now, perhaps by GPs, pharmacists or even as a home-test or is it more likely to be used only by hospital clinics?