A voluntary registry for peanut and tree nut allergy: Characteristics of the first 5149 registrants

Background: A voluntary registry of individuals with peanut and/or tree nut allergy was established in 1997 to learn more about these food allergies. Objective: The purpose of this study was to elucidate a variety of features of peanut and tree nut allergy among the first 5149 registry participants. Methods: The registry was established through use of a structured questionn aire distributed to all members of the Food Allergy and Anaphylaxis Network and to patients by allergists. Parental surrogates completed the forms for children under the age of 18 years. Results: Registrants were primarily children (89% of registrants were young er than 18 years of age: the median age was 5 years), reflecting the member ship of the Network. Isolated peanut allergy was reported by 3482 registran ts (68%), isolated tree nut allergy by 464 (9%), and allergy to both foods by 1203 (23%). Registrants were more likely to have been born in October, N ovember, or December (odds ratio, 1.2; 95% CI, 1.18-1.23; P < .0001). The m edian age of reaction to peanut was 14 months, and the median age of reacti on to tree nuts was 36 months; these represented the first known exposure f or 74% and 68% of registrants, respectively. One half of the reactions invo lved more than 1 organ system, and more than 75% required treatment, freque ntly from medical personnel. Registrants with asthma were more likely than those without asthma to have severe reactions (33% vs 21%; P < .0001). In c omparison with initial reactions, subsequent reactions due to accidental in gestion were more severe. more common outside the home, and more likely to be treated with epinephrine. Conclusions: Allergic reactions to peanut and tree nut are frequently sever e, often occur on the first known exposure, and can become more severe over time.