Food allergy - Twitter summary from EAACI-WAO Congress 2013

This summary was compiled from the tweets posted by allergists/immunologists who attended the EAACI-WAO Congress 2013. The tweets were labeled #eaaciwao2013. The text was edited and modified by me.

Dr. Gideon Lack discussed preventing peanut allergy, covering genesis of rationale for studying earlier introduction of foods vs. avoidance.

Peanut allergy is a result of skin sensitization before opportunity for oral tolerance.

Can we prevent peanut allergy by early introduction of peanut? LEAP study will give some answers. “LEAP-On” study will carry peanut exposure forward then stop to see if 'early' introduction lead to tolerance.

8 foods cause 90% of food allergies (click to enlarge the image). The likelihood of a negative oral food challenge is shown in relation to the respective values of skin prick test (SPT) and serum IgE (sIgE):



Atopic dermatitis and food allergy

Oozing crusting lesions with atopic dermatitis are linked with a 5 times greater risk for the development of peanut allergy.

Filaggrin mutation is an independent risk factor for peanut allergy regardless of AD status (Brown JACI article 2011).

Allergen labeling of foods

Dr. Ebisawa Motohiro talked on food allergy practice in Japan. Reminds us that desensitization after OIT does not equal tolerance. Helpfully, 'may contain' labels not allowed in Japan, the first country to mandate allergy labeling in 2002.

It should be noted that the vast majority of Japan's challenge and OIT experience is with egg and milk.

Allergen labeling is mandatory for added ingredients. Voluntary for precaution only. Although awareness of foods in which peanut is an ingredient is quite good, precautionary labeling is trickier.

Precautionary labeling only informs patients re: what to avoid. However, permissive labeling is urgently needed.

Threshold dose is ED01. Eliciting dose in 1% of allergic individuals is ED01. For peanut, ED01 is 25 times lower than ED for anaphylaxis. Threshold study for 5 foods published in JACI 2013;131:172-9. Bloom MW et al.

No way to predict severity of food allergic reactions

There is no way to predict allergic reactions (local vs. systemic, mild vs. severe). Therefore, oral food challenge (OFC) is still important in the diagnosis of food allergy. In OFC, both ends of the dosing curve are essential. Start too high, and you can elicit first dose reactions. End too low, and you risk missing allergy.

When is it worthwhile to pursue OFC?

- If sensitization is persistent
- If no history of recent reaction
- To help relieve anxiety

Desensitization vs. tolerance induction with OIT

Dr. Wesley Burks: desensitization (on therapy) vs. tolerance induction (off therapy). These definitions are critical. Interval off therapy to define achieving tolerance is not known (weeks, months or years).

"Sustained Unresponsiveness" is presently the preferred term to describe patients who were on OIT, stopped and had no reactions at that point. Length of OIT before stopping seems to correlate with likelihood of sustained unresponsiveness.

Chinese herbal therapy from Sampson's group now starting Phase II trials for food allergy.

Epinephrine

Intramuscular epinephrine injection to the thigh is superior to subcutaneous injection or injection in the arm. Less than 50% of patients initially prescribed epinephrine auto injectors actually refill the prescription upon expiration.

Some obese patients may not receive intramuscular injection with epineprine, due to needle length.

With EpiPen, 96% of epinephrine delivered after the 1st second of injection.

Component resolved diagnostics

Component resolved diagnostics may be helpful in the evaluation of false positive tests, geographical differences in sensitization, and longevity of allergy.

Ara h2 is the major allergen in peanut allergy. Evidence show it indicates more severe allergy.

In kiwi allergy, standard test only detects up 17% of allergic patients. Component test (act d1) detects up 77% of patients.

However, component resolved diagnostics are population specific, so more studies are needed.

Allergists are on Twitter - follow them

Allergists increased use of Twitter by 470% between 2011 and 2012. The service is very efficient in spreading the news from the annual scientific meetings, for example, 25 allergists reached 250,000 individuals from the 2012 #AAAAI meeting (see the references here).

This summary was compiled from some of the tweets posted by the following allergists:

John Fitzsimons @johnfitzsimons9
George du Toit ‏@GoAllergy
Allergy Nurse ‏@AllergyNurseUK
David Fischer, MD ‏@IgECPD
Sakina Bajowala, M.D ‏@allergistmommy

This is a list of the allergists who used Twitter to post updates from the 2013 #AAAAI meeting. The list is open for edit, please feel free to add your own info.