Anisakis simplex: sensitization and clinical allergy

PURPOSE OF REVIEW: Whereas gastric anisakiasis has been known for several decades, the implications of Anisakis simplex-related allergic disorders had not been thoroughly studied until the late 1990s. This article reviews recent knowledge of allergic disorders ascribed to A. simplex contact or parasitism. RECENT FINDINGS: Gastroallergic anisakiasis describes an acute hypersensitivity reaction emerging in the context of an acute parasitism by the nematode A. simplex. But other frequent allergic disorders like chronic urticaria are now being studied for a possible relationship with A. simplex parasitism. In recent investigations, non-IgE mediated mechanisms, such as the involvement of other immunoglobulin isotypes (IgG4), or non-immunological events are discussed. SUMMARY: The experience of the last several years shows that allergic hypersensitivity symptoms in gastroallergic anisakiasis are clinical events accompanying a wide range of immunologic reactions as a host response against a ubiquitous parasite. The discussed and reviewed studies should motivate allergists around the world to search for this entity. Further studies in the field of allergy could benefit from the experience of this peculiar food-related disorder.