Savage JH, Kaeding AJ, Matsui EC, Wood RA. Department of Medicine, Division of Allergy and Clinical Immunology, the Johns Hopkins University School of Medicine, Baltimore, Md. J Allergy Clin Immunol. 2010 Mar;125(3):683-686.

BACKGROUND:
Soy allergy is very common, affecting approximately 0.4% of children. It is generally thought that the majority of children with soy allergy develop tolerance in early childhood; however, this has not been examined in a large cohort with soy allergy.

OBJECTIVE:
We sought to describe the natural history of soy allergy and identify predictors of oral tolerance/outgrowing soy allergy.

METHODS:
The records of patients with soy allergy seen in a tertiary referral clinic were reviewed. Data collected included soy allergy-related symptoms, history of other food allergies and atopic diseases, soy-specific IgE levels, peanut-specific IgE levels, and food challenge results.

RESULTS:
One hundred thirty-three patients were studied (96 male and 37 female patients). Eighty-five (64%) had asthma, 95 (71%) had allergic rhinitis, and 108 (85%) had atopic dermatitis. Eighty-eight percent had concomitant peanut allergy. The median age at the initial visit was 1 year (range, 2 months to 17.5 years); the median duration of follow-up was 5 years (range, 1-19 years). Kaplan-Meier analysis predicted resolution of soy allergy in 25% by age 4 years, 45% by age 6 years, and 69% by age 10 years. By age 6 years, 59% of children with a peak soy IgE level of less than 5 kU/L, 53% of children with a peak s-IgE level of 5 to 9.9 kU/L, 45% of children with a peak s-IgE level of 10 to 49.9 kU/L, and 18% of children with a peak s-IgE level of greater than 50 kU/L had outgrown soy allergy (P < .01 for trend).

CONCLUSIONS:
In this referral population approximately 50% of children with soy allergy outgrew their allergy by age 7 years. Absolute soy IgE levels were useful predictors of outgrowing soy allergy. Copyright © 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

First published in March 2010

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