The natural history of soy allergy.
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.
Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md, USA.
Jessica H
JH
Savage
Allison J
AJ
Kaeding
Elizabeth C
EC
Matsui
Robert A
RA
Wood
D000293:Adolescent; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D005260:Female; D005512:Food Hypersensitivity / Q000097:blood / Q000453:epidemiology* / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007223:Infant; D008297:Male; D013025:Glycine max / Q000009:adverse effects* / Q000276:immunology*; D055815:Young Adult
D007073:Immunoglobulin E