Food allergy - Twitter summary from 2012 #AAAAI meeting

This summary was compiled from the tweets posted by the following allergists/immunologists who attended the 2012 annual meeting of the American Academy of Allergy Asthma and Immunology (AAAAI): Dr. Melinda Rathkopf ‏@mrathkopf, Dr. Ellis ‏‏@DrAnneEllis and David Fischer, MD‏ @IgECPD4. The tweets were labeled #AAAAI. The text was edited and modified by me.

Alpha-gal delayed anaphylaxis

Scott Commins from Thomas Platts-Mills' lab presented alpha-gal data and relevance to delayed anaphylaxis to meat. Dr. Cummins talked about delayed food challenge reactions and the role of alpha-gal. Alpha-gal is present on tissues and cells of lower mammals (beef, pork, lamb).

Delayed anaphylaxis occurs 3-6 hrs after eating mammalian meat (beef, pork, lamb). These delayed reactions following red meat consumption can be very late - in one case 7 to 8 hours later.

Prick testing is less helpful, intradermal testing can be positive. These patients have specific IgE to alpha-gal. However, most allergists are reluctant to perform IDT to foods in the office.

IgE to alpha-gal is associated with anaphylaxis but not asthma. It is unrelated to the presence of cat in home.

Most patients allergic to red meat are sensitized to gelatin. Alpha-Gal IgE might be the target of reactivity to gelatin (JACI, 2012).

Related reading: Ectoparasite-induced Galactose-α-1,3-Galactose–Specific IgE Is Associated with Anaphylaxis but Not Asthma http://goo.gl/tq86r

Food Allergy Pathogenesis and Prevention

There has been a dramatic increase in food allergy and eczema over the last 10 years. The burden is most notable in young children. For example, 1 in 10 children in Australia have challenge-proven IgE mediated food allergy.

When does food allergy start?

There are significant rates of food allergy prior to starting solid foods at 4-6 months of age. In these cases, consider in utero exposure and exposure through lactation. Fetus is highly responsive to antigens with a strong bias toward Treg differentiation. Allergen-specific Treg clles are generated in utero. Neonatal thymic TSLP level is lower in those who develop allergy.

Dietary interventions

Diet interventions restore n-3 PUFA status (fish oil). Fish oil was linked to reduction in eczema and egg sensitization. The study was just published in BMJ.

New studies are looking at restoring Vit D levels. Low vitamin D levels at birth are associated with increased risk of eczema.

The Allergy Epidemic: A Mystery of Modern Life by Dr. Susan Prescott is available online at: http://ebooks.readings.com.au/product/9781742583303

10% of Austrailan children have an oral food challenge-proven food allergy. 20% have food sensitization at early age.

The "Allergy Epidemic" is part of a much bigger problem - there is a dramatic rise over last 50 years in many chronic diseases. Dr. Prescott was pretty firm in her conclusion that probiotics do not have a role in the prevention of allergic disease today.

Early Dietary Exposures and Feeding Practices were discussed by Scott Sicherer, MD. There is Insufficient evidence that maternal dietary restriction during breast feeding prevents atopy.

A recent metaanalysis suggests breastfeeding not actually protective for developing atopy.

Vitamin D may improve skin barrier function and help with antimicrobial effects as well.

Diet for the prevention of asthma and allergies in early childhood: there are no evidence-based recommendations (http://goo.gl/j3Al8).

Food Allergy and Atopic Dermatitis (AD)

Food Allergy and Atopic Eczema (AD) were discussed by Dr. Gideon Lack. The question is: Does AD lead to food allergy or food allergy lead to AD?

80-90% of egg allergic children have atopic dermatitis. In children with AD, 27-81% have food allergy.

Infants with early onset (before 6 months of age) of eczema, had twice the rate of food allergies compared to those with late onset eczema.

Does food allergy cause AD? A study looked at eczema exacerbations following food challenges - 50% had a delayed eczematous reaction. The triggers were wheat, milk, egg and soy (the usual suspects).

Can dietary restriction improve AD? 15 of 16 studies showed some response but variable/small effect. Benefit were noted with egg, milk, wheat avoidance.

Loss of function filaggrin mutation was associated with 50% of moderate to severe eczema cases. However, filaggrin mutation does not play a role in African American patients with AD.

About 12% of AD patients in the US have defects in fillagrin (FLG).

Allergists achieved highest use of social media by any specialty

During the 2012 AAAAI meeting, the allergists achieved the highest use of social media by any specialty. There are more than 100 allergists on Twitter and 30 of them posted simultaneously from the annual meeting, broadcasting thousands of tweets tagged with #AAAAI. The annual AAAAI meeting was attended by approximately 5,000 people. In comparison, the 30 allergists on Twitter reached 250,000 people (measured by TweetReach.com on 03/04/2012).

This summary was compiled from some of the tweets posted by Dr. Melinda Rathkopf ‏@mrathkopf, Dr. Ellis ‏‏@DrAnneEllis and David Fischer, MD‏ @IgECPD4. I would strongly encourage you to post updates on Twitter from the CME conferences that you are planning to attend in the future. Here is how to do it: Twitter for Physicians: How to use Twitter to keep track of the latest news and scientific meetings, and share information with colleagues and patients.

Disclaimer: The text was edited, modified, and added to by me. This is one of a series of posts that will be published during the next few weeks.

Comments from Twitter:

Meenakshi Budhraja @gastromom: I wish Dr Susan Prescott was on Twitter.

David Fischer, MD ‏ @IgECPD4: @Allergy Thanks for your work...and you're welcome