Anaphylaxis due to hypersensitivity to Anisakis simplex.

Anaphylactic reactions are among the most frequent causes for requests for emergency medical care. It is possible that no clear precipitating factor can be found delaying the onset of adequate treatment and increasing the risk of new episodes of anaphylaxis in the future. Hypersensitivity to Anisakis simplex, an intestinal parasite found in fish, is an unusual cause of anaphylaxis but it should always be borne in mind in countries where a great deal of fish is consumed, especially if it is eaten raw or undercooked. 3 cases of anaphylaxis due to hypersensitivity to A. simplex are described.