Cutaneous Vasculitis: Review on Diagnosis and Clinicopathologic Correlations.

Cutaneous vasculitis is an inflammatory disease affecting the dermal blood vessel walls. The skin is a privileged organ in the setting of vasculitis since it is easily accessible for physical examination and safe biopsy, allowing an accurate characterization of inflammatory lesions. The skin is often involved. Also, cutaneous vasculitis can reflect a cutaneous component of a systemic vasculitis, a skin-limited or skin-dominant expression or variant of a systemic vasculitis, or be a single-organ vasculitis per se. Vasculitis lesions are multiple and polymorphic. They may induce a wide spectrum of clinical manifestations depending on the location and the size of the vessels involved. The depth of affected vessels is correlated with the type of cutaneous lesions. Involvement of small superficial vessels results mostly in urticarial, but relatively persistent plaques, papules, and palpable purpura. Involvement of vessels in the dermohypodermic junction or hypodermis results in ulcers, nodules, or livedo. The type of inflammatory infiltrate is also a key finding for the diagnosis of cutaneous vasculitis. Leukocytoclastic vasculitis is not a disease per se but the result of a pathophysiological process common to different causes. A better knowledge of the vascular anatomy of the skin, elementary lesions, and histological characteristics of dermatologic manifestations would allow a more relevant and more efficient diagnostic approach. We also propose a list of additional exams to be performed in front of skin lesions suggestive of vasculitis. The aim of our article is to provide an overview of elementary skin lesions and clinicopathologic correlations in cutaneous and systemic vasculitis.