Purpose of the Study. To define features of peanut (PN) and tree nut (TN) allergy among 5149 members of a voluntary registry.
Study Population. Food-allergic subjects (n = 5149) were enrolled from May 1977 to May 2000, with 75% voluntarily registered through membership in the Food Allergy and Anaphylaxis Network (FAAN) and 25% recruited by physicians. Eighty-nine percent of the registrants were children <18 years of age (median age = 5 years; 67% male). Only 16 individuals were ≥65 years of age (28% male).
Methods. A structured questionnaire was distributed to 7000 lay members and 1000 health professional members of the FAAN, as well as to 4000 members of the American Academy of Allergy, Asthma, and Immunology (AAAAI). Participants or parental surrogates provided demographic information and details about allergic reactions to PNs and TNs. Data were analyzed by χ2 analysis.
Results. Isolated PN allergy was reported by 3482 registrants (68%), isolated TN allergy was reported by 464 individuals (9%), and allergy to both by 1203 individuals (23%). Other self-reported food allergies included egg (29%), cow’s milk (22%), soy (11%), wheat (6%), fish (4%), and shellfish (2%). Atopic disorders included atopic dermatitis (50%), asthma (46%), and allergic rhinitis (27%). Participants were more likely to have been born in October, November, or December (P < .0001). Eighty-two percent (n = 3877) had been breastfed for a median of 7 months. The median age at first known exposure to PN was age 12 months (mean = 18.5 months), while the first known reaction was at a median age of 14 months (mean = 29.5 months). Seventy-four percent report that the first reaction to PN occurred with the first exposure, and ingestion was reported as the most common route of exposure (91%). The first reactions occurred primarily in the home, beginning a median of 3 minutes after exposure, 76% requiring medications. The median age at first known exposure to TN was 24 months (mean = 48 months), while the median age at first reaction to TN was 36 months (mean = 77 months). Sixty-eight percent reported that the first reaction occurred with the first exposure, and the majority of first TN reactions (61%) occurred in the home. Ingestion was the most common route of exposure to TN (88%). Half of all the reactions involved >1 organ system. A second reaction to PN was described by 2226 registrants (48%), and 1072 (23%) reported a third reaction. A second reaction to TN was reported by 564 people (34%) and 240 (14%) described a third. Subsequent PN and TN reactions attributable to accidental ingestion were more severe, more common outside the home and more likely to require treatment with epinephrine, when compared with initial reactions. Ninety percent of the participants reported having epinephrine available at all times. Of the 10% who did not, 45% had not been given a prescription.
Conclusions. This registry is the largest collection of patients with food allergies and emphasizes important and novel features of PN and TN reactions. Reactions are often severe, often occur on the first exposure, and require some type of medication or medical intervention. Subsequent reactions to PN and TN reportedly worsened in most patients. The majority of patients reported having epinephrine on hand, but it is worrisome that >500 patients did not have epinephrine readily available, and almost half of these patients had not ever been given a prescription.
Reviewers’ Comments. This study provides valuable insight into a very important aspect of food allergy. Because 89% of the registrants are children, this data is very valuable for pediatricians, as it provides new insights into the features of these PN and TN allergies, reaffirms previous observations, and provides a valuable source of information for health care providers.
- Copyright © 2002 by the American Academy of Pediatrics