Leukocytoclastic vasculitis
Leukocytoclastic vasculitis is the histologic and clinical pattern of small-vessel, immune-complex-mediated inflammation that produces palpable purpura, most often on the lower extremities, and is frequently drug-induced. Diagnosis rests on the clinical appearance confirmed by skin biopsy, and management starts with identifying and stopping the culprit drug or treating the underlying trigger, reserving glucocorticoids or steroid-sparing agents for extensive, ulcerative, or systemic (renal or gastrointestinal) disease.
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What this article covers
- Overview
Definition: leukocytoclastic vasculitis is the histopathologic pattern of small-vessel inflammation, most often confined to the skin, that produces the clinical picture of palpable purpura.
- Epidemiology
Occurs across ages: cutaneous small-vessel vasculitis and its drug-induced form can occur in adults of any age, while IgA vasculitis (Henoch-Schönlein purpura), a related immune-complex small-vessel…
- Risk factors
New or recently started medication: a temporal relationship to a new drug, particularly penicillins, cephalosporins, sulfonamide-containing diuretics, phenytoin, or allopurinol, is the leading identifiable trigger.
- Pathophysiology
Immune complex formation: in an immune complex-mediated (type III) hypersensitivity reaction, the drug (or another antigen) acts as a soluble antigen that binds drug-specific IgG, forming small immune complexes.
- Clinical features
Diagnostic lesion: palpable purpura, purpuric lesions that are raised and non-blanching to palpation, most often affecting the lower extremities.
- Differential diagnosis
IgA vasculitis (Henoch-Schönlein purpura): the same leukocytoclastic histology plus IgA deposition on immunofluorescence, together with the arthralgia-abdominal pain-hematuria tetrad, distinguishes…
- Diagnosis
The diagnostic basis is skin biopsy showing the leukocytoclastic pattern: a neutrophilic infiltrate with leukocytoclasis (nuclear dust) and fibrinoid necrosis of small vessel walls on histopathology…
- Management
First step: identify and stop the culprit drug, or treat the underlying trigger (infection or associated systemic disease); in most drug-induced and idiopathic cases this alone allows the eruption to…
- Complications
Renal disease: glomerulonephritis can complicate IgA vasculitis, particularly in adults, who carry a higher risk of renal involvement than children with the same diagnosis.
- Prognosis
Frequently self-limiting: many episodes, especially drug-induced cutaneous disease and pediatric IgA vasculitis, are self-limited and resolve once the trigger is removed or the underlying process runs its course.
- Prevention
Avoid re-exposure to any identified culprit drug: since rechallenge with the same or a higher dose can cause a more rapid and severe recurrence, document the association clearly and avoid the agent…
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