METHODS: Eighty-seven patients were included in this prospective monocentric study, 45 of whom were presenting a palpable purpura. Patients were classified in two categories: \"leukocytoclastic vasculitis\" or \"other diagnosis\". The clinical and histopathological features of patients with a palpable purpura were studied.
RESULTS: The mean age of patients presenting a palpable purpura was 69 years. There were 26 men and 19 women. Of the 43 patients biopsied, 37 were included in the vasculitis group. The sensitivity, specificity, positive predictive value and negative predictive value for a diagnosis of vasculitis in patients with palpable purpura were respectively 82, 65, 86 and 58 %. The Odds ratio was 8.48 (95 % CI, 2.52-31.80; P<0.05).
CONCLUSIONS: Most of the palpable purpuras examined were indeed related to leukocytoclastic vasculitis. In the remaining cases, biopsy did not contribute to the diagnosis since it only showed purpura without vessel wall inflammation. In our opinion, a skin biopsy is thus not essential where the clinical presentation is typical.