Delayed pressure urticaria: response to treatment with sulfasalazine in a case series of seventeen patients.

We retrospectively identified 17 patients with delayed pressure urticaria (DPU), diagnosed by history and confirmed with provocative pressure testing. The average age in the cohort was 42.6 years with 10 women and seven men. The mean duration of disease before diagnosis was 19.7 months (range, 1-60 months). The diagnosis of DPU was not included in the differential diagnosis of referring physicians and was not a diagnostic consideration in any of seven biopsies obtained. None of the patients responded adequately to treatment with antihistamines, but all 17 responded transiently when treated with either oral or intramuscular steroids. Eleven patients experienced complete or near complete resolution of DPU with treatment with sulfasalazine (SZ). Four patients had a partial response while two were unable to continue therapy because of drug intolerance. SZ appears to be a low cost and effective treatment for DPU.