J Investig Allergol Clin Immunol 2010; Vol. 20(5): 437-441 © 2010 Esmon Publicidad CASE REPORT Multiple Acute Parasitization by Anisakis simplex J Jurado-Palomo, 1 MC López- Serrano, 1 I Moneo 2 1 Department of Allergology, University Hospital La Paz, Madrid, Spain 2 Department of Immunology, Hospital Carlos III, Madrid, Spain ■ Abstract Hypersensitivity to Anisakis is an increasingly prominent medical problem throughout the world, due to a better understanding of diseases induced by parasites and to modern culinary habits of eating raw or undercooked fi sh. We describe the case of a patient who presented epigastric pain, wheals, erythema, and pruritus 3 hours after the ingestion of fi sh. More than 200 larvae were obtained by endoscopy. However, the patient only developed an immune response with specifi c immunoglobulin E and eosinophilia peaking at day 18 and decreasing during the 17-month follow-up. Only eosinophilia reached normal limits. Key words: Parasitization. Anisakis simplex. Ani s 1. Ani s 4. Recombinant allergen. ■ Resumen La hipersensibilidad a Anisakis simplex es un problema médico de distribución mundial cada vez con mayor relevancia debido tanto al mejor conocimiento de las enfermedades ocasionadas por parásitos como a los modernos hábitos culinarios de ingesta de pescado crudo o poco cocinado. Describimos el caso de una paciente que presentó epigastralgia, eritema, pápulas y prurito tres horas después de la ingesta de pescado. Se extrajeron más de doscientas larvas mediante endoscopia oral. A pesar de ello, sólo desarrolló una respuesta inmune con IgE específi ca frente a Anisakis simplex y eosinofi lia, alcanzándose la máxima respuesta a los 18 días tras la ingesta y descendiendo durante un seguimiento de 17 meses, aunque las cifras de eosinófi los retornaron al rango de normalidad. Palabras clave: Parasitación. Anisakis simplex. Ani s 1. Ani s 4. Alérgeno recombinante. Introduction Anisakis simplex is a nematode that can infect humans who eat raw or undercooked fish containing live L3 larvae. Larvae invading the gastrointestinal mucosa secrete proteins implicated in the pathogenesis of anisakiasis, which can induce immunoglobulin (Ig) E–mediated symptoms, with clinical manifestations ranging from urticaria or angioedema to anaphylaxis [1]. On infection by the parasite, humans develop specific IgE to parasite allergens. Further contact induces basophil and mast cell degranulation, thus leading to symptoms. When an Anisakis infection is suspected, correct diagnosis is based on a clinical history that is suggestive of fish ingestion, with oral panendoscopy as the test confirming diagnosis and, as in our case, enabling a therapeutic intervention to be made. Skin prick tests and determination of specific IgE to Anisakis are also routinely performed [2]. We report the case of a patient infected by a large number of A simplex larvae. Despite the quantity of allergen, she developed only minimal allergic symptoms and a weak immune response. Case Description A 37-year-old woman with no personal history of interest, presented epigastric pain, pruritus, diffuse erythema, and wheals (face, pressure points, and flexures) 3 hours after ingestion of fried hake and fish ova. She did not experience nausea or vomiting. Two hours later, she was admitted to