Risk factors in pediatric shrimp allergy

Background: The prevalence of shellfish allergy is ∼1.3% in the United States, with shrimp most commonly reported. Shellfish is one of the top causes of food-induced anaphylactic reactions, yet there are no reported rates of pediatric shrimp anaphylaxis in the literature. In previously reported adults with shrimp allergy, the rate of anaphylaxis to shrimp was 42%. Objective: To describe the rate of anaphylaxis among children with shrimp allergy, demographics, clinical presentation, and cross-reactive sensitization. Methods: Retrospective chart review of children ≤18 years old who presented with shrimp allergy to Texas Children's Hospital Allergy and Immunology Clinic over 11 years. Results: Sixty-eight patients were identified with shrimp allergy (61% male, 39% female), with a median age of diagnosis at 5.6 years (range, 0.96 -16.6 years). The rate of anaphylaxis was 12%, and mucocutaneous symptoms were most common (skin symptoms, 70%; urticaria, 58%; and angioedema, 58%). No factors were positively associated with anaphylaxis, whereas patients without anaphylaxis had a significantly higher rate of eczema compared with those with anaphylaxis (p = 0.02). African Americans and Asian Americans were disproportionately affected (p < 0.001). There were low rates of crosssensitization for other crustaceans and for mollusks (57% and 26%, respectively). Conclusion: The rate of anaphylaxis to shrimp was significantly lower in children with shrimp allergy than in adults, and anaphylactic reactions were negatively associated with eczema. Cross-reactivity to other crustaceans and mollusks does not uniformly occur. Prospective studies with double blinded placebo-controlled food challenges are needed to further characterize patients with shrimp allergy.