Acute allergic reactions to Anisakis simplex after ingestion of anchovies.

Anisakis simplex is a seafish nematode, which is responsible for the well-known human infection (anisakiasis) and can induce IgE-mediated reactions. IgE sensitization to Anisakis simplex can be frequent in particular countries and should be suspected in patients with acute allergic symptoms after ingestion of fish. The etiological role of Anisakis simplex was evaluated in 49 adult subjects with acute allergic symptoms after ingestion of anchovies. Serum-specific IgE and prick tests to anchovy were negative in each patient. Specific IgE reactions to Anisakis were positive in 45 patients and skin tests in 43. Only 3 patients with allergy to the nematode were atopic. However, IgE responses to Anisakis were also observed in habitual consumers of raw fish, without any clinical manifestations, suggesting that the relevance of results of conventional tests has to be interpreted on the basis of clinical aspects.