Vasculitis from the dermatological point of view

Abstract

In vasculitis, dermatologists generally examine two kinds of patient who present with small-vessel vasculitis as defined by the Chapel Hill Consensus Conference nomenclature, and idiopathic cutaneous polyarteritis nodosa (CPN). CPN is a vasculitis of small and medium-sized arteries within the skin that does not involve internal organs. When these patients visit my clinic, I characterize the cutaneous manifestations at initial presentation and assess the histopathological findings. In systemic antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, the characteristic cutaneous clinical pattern of microscopic polyangiitis is livedo reticularis, whereas Churg-Strauss syndrome presents as purpura and petechiae with paresthesias on the lower extremities. When a patient presents with nodules on the elbows with histological palisading granuloma, diagnosis of three ANCA-associated vasculitis including Wegener's granulomatosis should be considered. In immune-complex-mediated vasculitis, Henoch-Schönlein purpura (HSP) is characterized by palpable non-thrombocytopenic purpura on initial clinical presentation. These clinical cutaneous investigations in vasculitis patients may allow us to refine our earlier diagnostic strategies. On the other hand, histological examination in a cryoglobulinaemic vasculitis patient revealed microvascular thrombus and leucocytoclastic vasculitis in the dermis. From these findings, I speculated that the presence of thrombosis may be somehow related to the pathogenesis of the vasculitis process and investigated the association between vasculitis, especially immune-complex-mediated vasculitis, and antiphospholipid antibodies (Abs). Serum levels of IgA anticardiolipin antibody (aCL) are elevated in the initial active stage of adult HSP, suggesting that the IgA aCL may play some role in the onset of adult HSP. We also suggest that CPN could be dependently associated with the presence of anti-phosphatidylserine-prothrombin complex Abs.