Wednesday, 7 March 2012

Sublingual Immunotherapy-Allergic Reactions-Allergic Asthma-Food Allergies-Peanut Allergy

Food allergy - a Twitter summary from the 2012 WSAAI meeting

This summary was compiled from the tweets posted by @MatthewBowdish, an allergist/immunologist, who attended the 2012 Western Society of Allergy, Asthma and Immunology (WSAAI) meeting. The tweets were labeled #WSAAI. The text was edited and modified by me.
Dr. Scott Sicherer discussed Future Treatments of Food Allergy:
Current management of food allergy includes avoidance only if proven food allergen, nutritionist counseling, growth monitoring, and EpiPen for anaphylaxis.
Anti-IgE (omalizumab) treatment can raise thresholds for food allergic reactions in most patients. However, 25% of patients do not respond.
Chinese medicine formula FAHF-2
Traditional Chinese medicine formula FAHF-2 stops peanut-induced anaphylaxis in mice, and human trials are currently underway at Mount Sinai medical center.
Immunotherapy for peanut: previous injection IT worked but there were a lot of reactions. Now efforts are directed toward oral or sublingual immunotherapy. Allergists are also looking at rectal administration of attenuated peanut allergen.
Oral immunotherapy for food allergy reduces basophil activation but it doesn't promote tolerance (it is more like desensitization).
Reactions to the maintenance dosing of food oral IT were associated with exercise, viral illness and menstruation.
Patients on SLIT for peanut could take more peanut than oral IT with associated immunologic changes concurrent with desensitization. In general, SLIT was not as good as OIT.
OIT is not a cure for food allergy, but quite possibly a treatment.
Epicutaneous Immunotherapy (EPIT), using skin to promote tolerance, showed increased peanut cumulative dose from 1.8 ml to 26 ml. However, EPIT is based on a limited number of subjects.
70% of children who are allergic to egg or milk can tolerate extensively heated forms of the protein (e.g. cookies, cake).
Prevention of food allergy and atopy through diet
With prevention of food allergy through diet, one must look at sensitization, inflammation and allergic disease. There a difference in preventing allergic disease or delaying disease.
Breast feeding is good for everyone, especially when given exclusively for 4-6 months.
Having fish in maternal diet was protective against development of eczema (probably mediated through synthesis of PGE2).
Delaying introduction of solids is unlikely to be helpful in prevention of atopy. On the contrary, earlier introduction of solid food is now thought to be more protective. Late introduction of wheat, egg, milk, etc. were all assoc with increased risk of atopy. Allergists are awaiting Learning About Early Intro ("LEAN") study results for more evidence-based answers.
There is no evidence for restricting maternal diet while breast feeding. Soy formula selection doesn't protect against atopic disease.
There are some additional benefit for use of extensively hydrolyzed formula vs. partial one, but the number needed to treat (NNT) is high.
Risk factors for peanut allergy include soy consumption as infant, eczema, and use of topical ointments with peanut oil.
More peanut in environment (especially “messy” snacks like peanut butter) can cause more peanut allergy but ingestion of peanut is less likely to be associated with peanut allergy (i.e., early oral intake is good, but skin exposure is bad).
Sibling risk of peanut allergy is about 7%. Should we test siblings before introducing peanut?
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):
The jury is still out on the use of probiotics for treatment of atopy but they may be helpful in prevention (but there is no good evidence). It is well established that there are more bacterial cells in your body than the total number of your own cells.
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