[en] ABSTRACT: The association of chronic urticaria (CU) to parasitic infestations has been poorly studied. Recently, sensitization to the parasite larva Anisakis simplex has been described as the cause of acute urticaria and anaphylaxis. The aim of this work was to study the relationship between sensitization to A. simplex and CU. One hundred one patients with CU were studied. Data of possible contacts with A. simplex were collected and the usual CU study was performed. Furthermore, total and specific immunoglobulin E (IgE; Pharmacia CAP system IGE fluorescence enzyme immunoassay: CAP) to A. simplex, Ascaris lumbricoides, Echinococcus granulosus, and Toxocara canis were determined as well as skin-prick test with A. simplex and serology to E. granulosus. In accordance with the results of the CAP to A. simplex, the patients were divided into two groups, positive and negative, and, subsequently, subdivided into two other subgroups that were alternatively told to stop eating fish or seafood in their diet or to continue with their normal diet. Checkups were performed at 6, 12, and 18 months. Thirty-five percent of the patients had positive skin tests to A. simplex, and CAP to A. simplex was positive in 55%. The fish-eating habits, acute or chronic gastrointestinal disease, and the background of abdominal surgery were not related to the results of the CAP and/or skin test to A. simplex. A total of 21.8% of all the patients had detectable CAP to A. lumbricoides, 91% of whom had positive CAP to A. simplex. Three patients had specific IgE to T. canis and five patients had specific IgE to E. granulosus, in the absence of positive serology. All had specific IgE to A. simplex. Present infestation could not be proved in any of them. The clinical evolution and variations of CAP to A. simplex and of total IgE were not statistically different among the groups during the 6, 12, and 18 months of the study. The percentage of sensitization to A. simplex in patients with CU is elevated and determines the sensitization to other parasites because of cross-reactivity. We have not found any causal relationship between the presence of specific IgE to A. simplex and CU. The clinical importance of this finding in this disease is still undetermined.

[es] La asociación entre la urticaria crónica (UC) y las infestaciones parasitarias ha sido escasamente investigada. Recientemente, se ha descrito que la sensibilización a la larva del parásito Anisakis simplex puede ser causa de urticaria aguda y anafilaxia. El objetivo de este estudio fue analizar la posible relación entre la sensibilización a A. simplex y la urticaria crónica. MÉTODOS Se estudiaron 101 pacientes con diagnóstico de urticaria crónica. Se recogieron datos sobre posibles contactos con A. simplex y se realizó el estudio habitual de UC. Además, se determinaron los niveles de inmunoglobulina E total y específica (IgE; sistema Pharmacia CAP, inmunoensayo enzimático fluorescente) frente a A. simplex, Ascaris lumbricoides, Echinococcus granulosus y Toxocara canis. También se realizaron pruebas cutáneas por punción con A. simplex y serología para E. granulosus. Según los resul... RESULTADOS El 35 % de los pacientes tuvo pruebas cutáneas positivas para A. simplex, y el CAP fue positivo en el 55 %. Los hábitos alimentarios relacionados con el consumo de pescado, la existencia de enfermedades gastrointestinales agudas o crónicas, y los antecedentes de cirugía abdominal no mostraron relación con los resultados del CAP o de las pruebas cutáneas a A. simplex. El 21,8 % de los pacientes presentaba CAP detectable frente a A. lumbricoides, de los cuales el 91 % también mostraba CAP positivo para A... CONCLUSIONES El porcentaje de sensibilización a A. simplex en pacientes con urticaria crónica es elevado y se asocia con sensibilización a otros parásitos debido a reacciones cruzadas. No se ha encontrado una relación causal entre la presencia de IgE específica frente a A. simplex y la urticaria crónica. La relevancia clínica de este hallazgo en esta enfermedad permanece aún por determinar.