Association of inflammation and necrosis of blood vessels of the skin.
Typical primary skin lesion of small vessel cutaneous vasculitis is palpable purpura with lesions ranging in size from 1mm to several centimeters.
Lesions arise as a simultaneous crop and result from the exposure to an inciting event.
A wide array of lesions may be involved including: macules, papules, nodules, vesicles, plaques, bullae, and pustules.
A number of secondary changes may occur and include ulcerations, necrosis, and hyper pigmentation.
Other possible associated skin lesions include urticaria, livedo, reticularis and edema
Lesions most commonly on dependent sites especially the ankles and lower legs and other areas of stasis.
Usually asymptomatic but may have local symptoms such as pain, burning or pruritus.
Classified according to the size and location of involved blood vessels and the type of inflammatory infiltrate identified by biopsy.
Immunofluorescence testing and serologic testing help define the type of vasculitis.
Serologic testing for anti-neutrophil cytoplasmic antibodies (ANCA), cryoglobulins, and complement components helps define the process.
If systemic symptoms are present such as arthralgias or myalgias, suggests an association with a systemic disease.
Usually 50% of cases are acute or transient , while 30% have chronic disease, and 20% experience relapsing disease.
All patients should be evaluated for the presence of systemic disease.
Histologic hallmark for small vessel cutaneous vasculitis is leukocytoclastic vasculitis.
Microscopic examination reveals infiltration of blood vessels with neutrophils, neutrophil degranulation and fragmentation (leukocytoclasia), fibrinoid necrosis, swelling and proliferation of endothelial cells.