GASTRIC ANISAKIASIS - AN UNDERESTIMATED CAUSE OF ACUTE URTICARIA AND ANGIO-EDEMA

Acute urticaria and angio-oedema are common in primary care and in the emergency unit. Food allergy is one possible cause. We describe gastr ic anisakiasis, in which symptoms are often not obviously related to e ating raw fish. A study was made of patients presenting at the emergen cy department who had allergic symptoms such as urticaria or angio-oed ema and had recently eaten raw or undercooked fish. They were divided into two groups. Patients in group A (n = 13) also had abdominal sympt oms and were diagnosed as having gastric anisakiasis by fibre-optic ga stroscopy where I-bird-stage larvae of Anisakis simplex were visualize d and extracted, skin prick tests and specific IgE to A. simplex were positive. Patients in group B (n = 13) had only allergic symptoms afte r eating raw fish. Eleven of 13 patients had positive skin prick tests and specific IgE to A. simplex. three of 15 control subjects had posi tive skin prick tests and specific IgE to A. simplex. Allergic symptom s appeared from 2 to 20 h (mean 5.0) after ingestion in group A and fr om 20 min to 23 h (mean 4.3 h) in group B. Gastric symptoms in group A disappeared rapidly after extraction of the larvae, Allergic symptoms disappeared in most cases within the first 24 h. We suggest that the allergic symptoms in group A as well as in group B were mainly due to parasitization by A. simplex in sensitized patients. Gastric anisakias is may be a widely underdiagnosed clinical entity.