[A Decade of Oral Immunotherapy at Shamir Medical Center (Assaf Harofeh): Efficacy, Safety and Unresolved Questions]

The reported prevalence, as well as the awareness of food allergies are increasing in western countries. Food allergy is associated with adverse reactions which could be fatal, present nutritional deficiencies, and have a significant impairment in the quality of life. In recent years, oral immunotherapy for food allergy has become available.

To study the efficacy and safety of oral immunotherapy (OIT) for food allergy at Shamir Medical Center over a 10-year period.

A retrospective cohort study of all patients who completed OIT for food allergy at Shamir Medical Center and reached a final disposition of full or partial desensitization, or treatment failure between April 2010 and December 2020.

A total of 1519 patients completed 1704 OIT treatments, at a median age of 7.4 years (range 3.7 - 36.5 years) during this time period. Of those, 61% were males, 65.5% had house-dust mite sensitization, and 48.7% had asthma. The foods treated were milk (n=862, 50.6%), peanut (n=361, 21.2%), tree nuts (n=275, 25.6%), sesame (n=131, 7.7%), and egg (n=75, 4.4%). Epinephrine-treated reactions were experienced in 335 (19.7%) OIT treatments in the clinic during the first week of treatment, and by 203 (11.9%) treatments for home doses. Overall, 1228 (72.1%) treatments have reached a final disposition of full desensitization, 306 (18%) reached partial desensitization, and 170 (10%) failed. The most significant risk factor for treatment failure on multivariate analysis was milk OIT (OR=2.9, p<0.001). Additional risk factors for treatment failure were asthma (p=0.02), a larger wheal size on skin prick test, and a lower tolerated dose, at the beginning of OIT (p=0.02 and p=0.01, respectively), and epinephrine-treated reactions in the clinic during the first week (p<0.001), or for home doses (p<0.001). Milk-treated patients had a higher prevalence of asthma, and more anaphylactic and epinephrine-treated reactions on accidental consumption before OIT, as well as during up-dosing and home doses during the treatment (p<0.001 for all variables).

OIT for food allergy is highly effective but is associated with adverse reactions, including home reactions requiring epinephrine, and certain limitations are required during home dosing. Milk OIT is associated with more severe reactions and with lower efficacy. It is important to discuss risks, benefits, and expectations with patients wishing to undergo OIT.