Prevalence of seafood allergy in the United States determined by a random telephone survey

Background: Seafood allergy is potentially severe, but the prevalence of this group of food allergies in the US population has not been determined. Objective: To estimate the prevalence of seafood (fish, shellfish) allergy in the United States. Methods: We performed a nationwide, cross-sectional, random telephone survey by using a standardized questionnaire. Criteria were established in advance to define seafood allergy by report of convincing symptoms and physician evaluation. Results: A total of 5529 households completed the survey (67.3% participation rate), representing a census of 14,948 individuals. Fish or shellfish allergy defined by established criteria was reported in 5.9% (95% CI, 5.3%-6.6%) of households and among individuals as follows: 2.3% (95% CI, 2%-2.5%) for any seafood allergy, 2% for shellfish, 0.4% for fish, and 0.2% for both types. Seafood allergy was more common in adults compared with children (2.8% vs 0.6%; P < .001) and in women compared with men (3.6% vs 2%; P < .001). Recurrent reactions were reported by 58%, dyspnea or throat tightness was reported by more than 50%, and 16% were treated with epinephrine. Despite this level of acuity, only 8.6% were prescribed self-injectable epinephrine. The rate of reactions to multiple fish among those with any fish allergy was 67%; for Crustacea the rate was 38%, and for mollusks the rate was 49%; only 14% with crustacean allergy reported a mollusk allergy. Conclusions: Physician-diagnosed and/or convincing seafood allergy is reported by 2.3% of the general population, or approximately 6.6 million Americans. Affected individuals typically report recurrent and sometimes severe reactions, indicating that seafood allergy represents a significant health concern.