J Allergy Clin Immunol. 2010 (Mar); 125 (3): 683–686
Jessica H. Savage, Allison J. Kaeding, Elizabeth C. Matsui, Robert A. Wood
Department of Medicine,
Division of Allergy and Clinical Immunology,
Johns Hopkins University School of Medicine,
Baltimore, Md, USA.
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.