Cutaneous small-vessel vasculitis (CSVV), also known as hypersensitivity vasculitis, cutaneous leukocytoclastic vasculitis, hypersensitivity angiitis, cutaneous leukocytoclastic angiitis, cutaneous necrotizing vasculitis and cutaneous necrotizing venulitis, is inflammation of small blood vessels (usually post-capillary venules in the dermis), characterized by palpable purpura. : 831  It is the most common vasculitis  seen in clinical practice. "Leukocytoclastic" refers to the damage caused by nuclear debris from infiltrating neutrophils in and around the vessels. Signs and symptoms
Skin lesions
Initially red to pink, flat spots (formally, "macules") and raised bumps (formally, "papules") may be seen on the skin.Once fully developed, the classic appearance is "non-blanching, palpable purpura". This appears as deep red to purple spots that feel raised to the touch. Purpura refers to the red-purple discolored spots, while palpable implies that these spots can be felt as raised from the surrounding skin. Additionally, when gently pressed, the color does not fade to a lighter color ("non-blanching"). The red-purple color of the lesions is due to the inflammation in the blood vessels causing red blood cells to escape into the dermis skin layer.Small fluid-filled blisters (or "vesicles"), pus-filled bumps resembling a pimple (or "pustules"), or shallow ulcers may also develop but are less common.The location of skin lesions varies but are most commonly found symmetrically below the waist, primarily on the buttocks and legs.
Small vessel cutaneous vasculitis is a diagnosis of exclusion and requires ruling out systemic causes of the skin findings. Skin biopsy (punch or excisional) is the most definitive diagnostic test and should be performed with 48 hours of appearance of the vasculitis. A skin biopsy will be able to determine if the clinical findings are truly due to a vasculitis or due to some other cause. Classification
Subtypes of small-vessel vasculitis include:: 833–6 
IgA vasculitis (Henoch-Schönlein purpura)
Acute hemorrhagic edema of infancy
Urticarial vasculitis
Cryoglobulinemic vasculitis
Erythema elevatum diutinum
Granuloma faciale
ANCA-associated vasculitis
Arthropod bites
Platelet dysfunction or deficiency
Cholesterol emboli
Septic emboli
Livedoid vasculopathy

Treatment
Treatment should be directed towards the specific underlying cause of the vasculitis. If no underlying cause is found and the vasculitis is truly limited to the skin then treatment is primarily supportive. Such treatment involves measures such as leg elevation, stockings, and topical steroids to relieve itching/burning. If the vasculitis does not self-resolve within 3–4 weeks, more aggressive treatment may be warranted. Oral colchicine or dapsone are often used for this purpose. If rapid control of symptoms is needed, a short course of high-dose oral steroids may be given. Immunosuppressive agents such as methotrexate and azathioprine may be used in truly refractory cases not responsive to colchicine or dapsone. Additional images
See also
Skin lesion
List of cutaneous conditions

References


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