Anaphylaxis to shellfish by inhalation of cooking vapor in a child

Crustacean allergy is more common in adults than in children, in which prevalence is less than 0.5%. Allergic symptoms to seafood are usually triggered by ingestion, but can also occur by inhalation of aerosolized proteins during trapping, processing, and cooking. Seafood allergy by inhalation is commonly reported in occupational settings, usually associated with respiratory symptoms, whereas it is rarely reported in children or as a cause of anaphylaxis. Herein, we describe the case of a 10-year-old girl referred to our allergy clinic for an acute episode of urticaria-angioedema of the face and trunk and difficulty breathing a few minutes after breathing in vapors from cooked shrimp, which resolved after administration of intramuscular epinephrine in the emergency department. The girl has a history of atopic dermatitis during early infancy and a few previous acute urticarial reactions involving to the face after ingestion of crustaceans and mollusks, which lead to an elimination diet for these foods without having performed any allergy evaluation. Serum-specific IgE came positive for crab, lobster, oyster, Pen a 1 (shrimp tropomyosin and Der p 10 (house dust mites tropomyosin) confirming the diagnosis of IgE-mediated allergy to crustaceans and molluscs. Tropomyosin is the major invertebrate pan-allergen found in all edible crustacean and mollusc species with a highly conserved amino acid sequence, which can cause clinical and IgE cross-reactivity among different invertebrate allergen sources. Tropomyosin is highly heat-stable protein, which can even increase it allergenicity after heat treatment. This feature can explain allergic reaction by inhalation of crustacean cooking vapors.