Peanut and tree nut allergic reactions in restaurants and other food establishments

Background: The clinical features of food-allergic reactions in restaurants and other food establishments have not been studied. Of the registrants in the United States Peanut and Tree Nut Allergy Registry (PAR), 13.7% have r eported reactions associated with such establishments. Objective: The purpose of this study was to determine the features of aller gic reactions to peanut and tree nut in restaurant foods and foods purchase d at other private establishments (eg, ice cream shops and bakeries). Methods: Telephone interviews were conducted through use of a structured qu estionnaire. Subjects/parental surrogates were randomly selected from among the 706 PAR registrants who reported a reaction in a restaurant or other f ood establishment. Results: Details were obtained for 156 episodes (29 first-time reactions) f rom 129 subjects/parental surrogates. Most reactions were caused by peanut (67%) or tree nut (24%); for some reactions (9%), the cause was a combinati on of peanut and another nut or was unknown. Symptoms began at a median of 5 minutes after exposure and were severe in 27% of reactions. Overall, 86% of reactions were treated (antihistamines, 86%; epinephrine, 40%). Establis hments commonly cited were Asian food restaurants (19%), ice cream shops (1 4%), and bakeries/doughnut shops (13%). Among meal courses, desserts were a common cause (43%). Of 106 registrants with previously diagnosed allergy w ho ordered food specifically for ingestion by the allergic individual, only 45% gave prior notification about the allergy to the establishment. For 83 (78%) of these 106 reactions, someone in the establishment knew that the f ood contained peanut or tree nut as an ingredient; in 50% of these incident s, the food item was "hidden" (in sauces, dressings, egg rolls, etc), visua l identification being prevented. In 23 (22%) of the 106 cases, exposures w ere reported from contamination caused primarily by shared cooking/serving supplies. In the remaining 21 subjects with previously diagnosed allergy, r eactions resulted from ingestion of food not intended for them, ingestion o f food selected from buffet/food bars, or skin contact/inhalation (residual food on tables, 2; peanut shells covering floors, 2; being within 2 feet o f the cooking of the food, 1). Conclusions: Restaurants and other food establishments pose a number of dan gers for peanut- and tree nut-allergic individuals, particularly with respe ct to cross-contamination and unexpected ingredients in desserts and Asian food. Failure to establish a clear line of communication between patron and establishment is a frequent cause of errors.