The clinical and laboratory findings affecting the response to oral cyclosporine therapy in 15 chronic idiopathic urticaria (CIU) patients (mean age 40 years) were investigated. The results were compared with 147 normal controls (mean age 53.9 years). The initial cyclosporine dose was 3 mg/kg/day; after 3 months the dose was tapered and discontinued over 1 month. All patients responded to cyclosporine, with a mean time to resolution of 11.3 weeks. High-sensitivity C-reactive protein (hs-CRP) was elevated at baseline in 9 of 15 patients. In these 9 patients, the treatment duration was significantly shorter in those with hs-CRP elevation compared to those in whom it was not elevated (8.7 months vs. 15.3 ...