Objective: To examine the incidence and clinical features of adults with biopsy proven cutaneous vasculitis (CV) associated with drugs.
Methods: Retrospective study of an unselected population of adults (age >20 years) with biopsy proven leukocytoclastic CV from 1988 through 1997. Drug associated CV was considered if CV was confirmed by a skin biopsy and there was a history of drug use within one week before the development of CV. Drug associated CV was classified by American College of Rheumatology (ACR) criteria. To differentiate Henoch-Schonlein purpura (HSP) from hypersensitivity vasculitis (HV), the traditional criteria proposed by Michel, et al were used (J. Rheumatol. 1992;19:721-8).
Results: Thirty-three of 138 patients (23.9%) presenting with biopsy proven CV were diagnosed with drug associated CV. The annual incidence rate of biopsy proven drug associated CV in adults was 17.49 cases/million (95% CI 11.53-23.46): men 25.10/million (95% CI 14.85-35.36), women 10.31/million (95% CI 3.92-16.70). Antibiotics (n = 13), especially amoxicillin, and analgesics or nonsteroidal anti-inflammatory drugs (n = 11) were the drugs more commonly associated with CV. All adults with drug associated CV met the ACR classification criteria for HV or HSP. Based on Michel's criteria 26 patients (78.8%) were classified as having HV and 7 HSP. No patient met ACR criteria for other systemic vasculitides. Complete recovery with no sequelae was observed in most cases.
Conclusion: Among patients with CV, drug associated disease is common and usually has a good clinical outcome.