Skin involvement in ANCA-associated vasculitis.

The skin is a common target organ in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Skin lesions may present as the initial manifestation or as the associated cutaneous manifestations in ANCA-associated vasculitis. Visually assessing the cutaneous manifestations and performing a biopsy of skin lesions to facilitate histopathologic confirmation are highly valuable diagnostically. Vasculitis (which affects dermal small vessels and subcutaneous muscular vessels) and nonvasculitic inflammation cause various types of skin lesions. The coexistence of different levels of vasculitis and nonvasculitis can occur in one or in several lesions or on different occasions. These puzzling clinical and histopathologic features may be closely related to the disease activity. Understanding the complicated clinical and histopathologic spectrum of skin lesions will contribute to the early diagnosis of ANCA-associated vasculitis with cutaneous complications.