Background: The cutaneous manifestations of microscopic polyangiitis (MPA) and polyarteritis nodosa (PAN) have not been compared since their distinction. Objectives To compare the clinical and pathological cutaneous manifestations in a series of patients with systemic MPA and PAN.
Methods: Patients with MPA (n = 162) and PAN (n = 248) from the database of the French Vasculitis Study Group were diagnosed according to the American College of Rheumatology and/or the Chapel Hill Consensus criteria. Purpura, livedo, nodules, urticaria, skin necrosis, oral and genital ulcers were recorded when present. Fifty-five skin biopsies were analysed. Clinical and histological skin data were compared in the following groups: MPA, PAN and two PAN subsets: PAN with and PAN without hepatitis B infection. The prevalence of systemic and biological manifestations were analysed in relation to the presence or absence of skin lesions. The chi(2) test was used for statistical studies.
Results: Cutaneous manifestations were present in 44% of MPA and PAN. Purpura was the most frequent manifestation (26% cases of MPA vs. 19% cases of PAN, P = 0.026). Urticaria was more frequent during PAN (6% vs. 1.2%, P = 0.015). Skin lesions were more frequent during PAN in the absence of HBV infection (54% vs. 30%, P < 0.05). No significant difference was detected from the histological data. Patients with skin lesions (either MPA or PAN) presented arthralgias and ocular manifestations more frequently. Mononeuritis multiplex was associated with skin lesions in the MPA group (P < 0.05).
Conclusions: The clinical or histological analysis of cutaneous lesions is not helpful for distinguishing PAN from MPA.