Recidivous acute urticaria caused by Anisakis simplex.

This study aimed to determine the cause of acute recidivous urticaria in patients who usually eat fish or other seafood. Twenty-five patients were studied. The skin prick test with larval Anisakis simplex extract was performed; total and specific IgE against A. simplex was measured with the CAP System; specific antibodies to A. simplex were determined by ELISA; and immunorecognition patterns of the sera were studied by Western blot. Nineteen patients showed specific IgE to A. simplex, but specific IgE to Ascaris was demonstrated in only two patients. No patients reacted to Toxocara canis or Echinoccocus granulosus antigens with the same test. The skin prick test was positive in 16 patients, in two of them persisting for 48 h. Five patients showed neither skin reaction nor specific IgE to A. simplex. Sera showed specific immunoglobulin levels against A. simplex larval crude extract, by both ELISA and Western blot. Likewise, specific immunoglobulin levels against excretory-secretory antigen were also measured by ELISA. Only one patient showed sensitization to fish. A. simplex was found to be the main cause of acute recidivous urticaria in patients who usually eat fish and are not sensitized to it.