Approaches to diagnosing anisakis allergy

Anisakis is a parasitic nematode which infects fish and can cause gastrointestinal disease if accidentally ingested. Infection can be accompanied by severe allergic reactions such as urticaria, angio-oedema and anaphylaxis. Furthermore, workers involved in fish processing can develop occupational allergy to Anisakis, including asthma, rhinoconjunctivitis and protein contact dermatitis. Diagnosis of allergy to Anisakis relies on skin-prick tests and the detection of specific IgE by ImmunoCAP. Since Anisakis infests fish, fish allergy should be investigated in symptomatic patients. Anisakis proteins also demonstrate considerable immunological crossreactivity to proteins of related nematodes and other invertebrates such as house-dust mites and cockroaches; this needs to be borne in mind when the diagnosis is made. This review outlines the approaches that have been used to increase the specificity of Anisakis diagnosis, including the use of immunoblotting and the identification of Anisakis allergens.