Chronic urticaria and cancer: an epidemiological study of 1155 patients.

To evaluate the possible association of malignant disease with chronic urticaria 1155 consecutive cases with chronic urticaria were reviewed. The Swedish Cancer Registry, Stockholm, was searched for records reporting malignancies in the study population (1958-84), and the expected number of malignancies was calculated on the basis of age- and sex-standardized incidence data. A malignancy was diagnosed in 36 patients with urticaria and the expected number of malignancies was 41. In 23 patients the malignancy appeared during the same year as the onset of urticaria or later. The expected number was 25.6. We conclude that chronic urticaria is not statistically associated with malignancy in general.