Urticarial vasculitis: etiologies and clinical course.

Out of 64 patients diagnosed with urticarial vasculitis (UV), 49 (76.6%) presented with their first attack of UV. The others experienced recurrent attacks with a mean number of 3.3 past recurrences. Fifteen patients had angioedema (23.4%) and 16 (25%) suffered systemic involvement. The most common abnormal laboratory finding was an increased erythrocyte sedimentation rate. Six of 62 patients (9.7%) had decreased C3 levels. A cause could be identified in 19 patients (29.7%). The most common identified cause was infection; other causes included drugs, malignancy and systemic lupus erythematosus (SLE). The prevalence of immunoreactant deposits in the skin lesions measured by DIF was 54.7% (35 of 64 patients). The median disease duration of each episode was 85 days. The probability that patients were free of symptoms within one year was 70%. Patients with an idiopathic cause had a statistically significant longer course duration of each episode than the group with upper respiratory tract infection. Compared to reports from Westem countries, our patients seemed to have less severe symptoms and a lower percentage of hypocomplementemic UV and SLE.