PURPOSE OF THE STUDY.
Previously published oral desensitization protocols require weeks to months. The current study evaluates the safety, efficacy, and immunologic effects of a rapid egg oral desensitization protocol.
Twenty-three patients between 5 and 17 years of age with symptomatic immunoglobulin (Ig) E-mediated egg allergy were recruited from the Allergy Clinic of Ciudad Real General Hospital. Patients had a clinical history of IgE-mediated egg allergy and at least 1 of the following: a positive skin prick test to commercial egg extract, detection of serum specific IgE (>0.35 kU/L) to egg white or its proteins measured by fluorescence enzyme immunoassay, a positive oral challenge test within the previous 3 months, or an unequivocal history of reaction to egg within the previous 3 months.
Skin prick testing to pasteurized raw egg white and commercial extracts of egg, egg white, ovalbumin, and ovomucoid were performed before desensitization and at 3, 6, and 12 months after desensitization. Egg-specific IgE and IgG were measured before desensitization; at week 3; and at 3, 6, and 12 months after desensitization. Desensitization was achieved when the patient tolerated 1 whole cooked egg (30 mL of egg white) and 8 mL (1/4 of white of whole egg) of raw egg white. The desensitization was planned for a 5-day period but was individualized for each patient based on adverse reactions. Variables measured in-cluded the number and severity of adverse reactions, minimum dose that triggered symptoms, days until tolerance to a whole cooked egg, skin prick test wheal size, and egg-specific IgE and IgG before desensitization and during the minimum 6-month follow-up period.
Twenty (86.9%) of the 23 patients achieved tolerance to a whole cooked egg. Fourteen patients achieved tolerance within 5 days. Six patients achieved tolerance in <10 days. One patient discontinued desensitization due to repeated gastrointestinal adverse reactions. Two patients were switched to a slow desensitization protocol and achieved tolerance in 60 and 80 days, respectively. Eighteen patients experienced at least 1 adverse reaction during desensitization. There were 35 mild and 20 moderate reactions. Desensitization led to a fall in the mean values of skin prick test wheal size and specific IgE levels significant at 6 months after desensitization and an increase in specific IgG levels significant at 3 weeks after desensitization.
The described protocol is safe and effective but must be performed in a highly supervised setting. Egg allergic patients can be desensitized within 5 days, without increased risk compared with earlier reported, slower protocols.
Egg is a common ingredient in a wide variety of foods. Desensitizing egg-allergic patients would reduce the risk of anaphylaxis associated with accidental ingestion and allow patients to consume a broader diet. Although the current study shows great promise, oral desensitization has significant inherent risks. Additional studies addressing patient selection, dosing, and long-term tolerance are essential before rapid oral desensitization becomes a commonly performed procedure.
- Copyright © 2012 by the American Academy of Pediatrics