Cutaneous small-vessel vasculitis (CSVV) represents the deposition of immune complexes in small blood vessels with subsequent vessel damage and blood extravasation (pathologically described as leukocytoclastic vasculitis). Nonblanching, purpuric macules and initially erythematous papules frequently coalesce into violaceous plaques (“palpable purpura”). The lower extremities and dependent areas of the back and buttocks are frequently involved. Pruritus can be significant or not present. Vesicles, ulcers, and necrosis may evolve within the purpuric lesions. Lesions appear over a few days and usually resolve with hyperpigmentation over 4 to 6 weeks. Symptoms may be minimal or include fever, arthralgias, myalgias, and malaise.
CSVV is associated with connective tissue diseases, malignancies, medications (cephalosporins, penicillins, sulfonamides, minocycline, thiazides, allopurinol, phenytoin, NSAIDs, oral contraceptives, antithyroid agents), infections (group A β-hemolytic streptococci, Mycobacterium leprae, viral hepatitis, HIV), and idiopathic subtypes (Henoch-Schönlein purpura [HSP], acute hemorrhagic edema of childhood).
HSP is a unique form of CSVV with palpable purpura of the lower extremities and buttocks. Occasionally, the lesions may be found on the upper extremities, trunk, and face. A recent respiratory infection, arthralgias, abdominal pain, and hematuria are common. Renal vasculitis can occur in up to 40%, but chronic renal impairment occurs in only 1% to 3%. Adults tend to have necrotic lesions (rare in children), as well as a higher incidence of renal impairment.
Management and Disposition
Recognition that a diverse group of entities can trigger CSVV is the 1st step. Evaluation for systemic symptoms (fever or other signs of infection, hematuria, gastrointestinal bleeding, and neurologic symptoms) requiring admission and appropriate consultation should be undertaken. Most cases are self-limited and only require supportive care (rest, elevation of extremities, antihistamines, and analgesics). Systemic symptoms require admission and consideration of corticosteroids and other immunosuppressants. Dermatologic referral for mild CSVV cases is indicated, and if systemic symptoms are present, ED consultation may help expedite the diagnosis. HSP requires dermatologic consultation as well as appropriate specialty consultations.
Leukocytoclastic Vasculitis. Lower extremities with erythematous papules and dorsal foot with erythematous plaques. If you were to run your finger across these lesions, they would be raised and not blanch. (Photo contributor: Lawrence B. Stack, MD.)
Leukocytoclastic Vasculitis. Acute necrotic leukocytoclastic vasculitis. (Photo contributor: J. Matthew Hardin, MD.)
Leukocytoclastic Vasculitis. Note the erythematous papules beginning to coalesce. These would not blanch with pressure. (Photo contributor: J. Matthew Hardin, MD.)
Henoch-Schönlein Purpura. Note the classic acral distribution of HSP (both upper and lower extremities, raising concern for renal involvement). (Photo contributor: Kevin J. Knoop, MD, MS.)