Cutaneous vasculitis encompasses a spectrum of disorders characterized by vessel wall inflammation resulting in purpura, nodules, ulcers, and livedoid changes. Small-vessel neutrophilic vasculitis—classically leukocytoclastic vasculitis (LCV), also termed cutaneous small-vessel vasculitis (CSVV)—presents with palpable purpura on dependent areas. Etiologies include infections, drugs, autoimmune/connective tissue diseases, malignancy, and cryoglobulinemia; many cases are idiopathic. Diagnosis relies on targeted history, exam, and timely biopsy with direct immunofluorescence (DIF). Treatment focuses on removing triggers, supportive care, and tiered anti-inflammatory or immunosuppressive therapy for severe, recurrent, or systemic disease.
Classification by Vessel Size and Patterns
- Small vessel (postcapillary venules): LCV/CSVV, IgA vasculitis, urticarial vasculitis, ANCA-associated vasculitides (AAV: GPA, MPA, EGPA; cutaneous purpura and ulcers).
- Medium vessel: cutaneous polyarteritis nodosa (cPAN), nodular panniculitis with livedo racemosa; ulcers/gangrene possible.
- Immune-complex–mediated patterns: IgA vasculitis (Henoch–Schönlein), hypocomplementemic urticarial vasculitis, cryoglobulinemic vasculitis.
Etiology and Triggers
- Infections: streptococcal, staphylococcal, hepatitis B/C, HIV, endocarditis.
- Drugs (common): antibiotics (beta-lactams, TMP-SMX), thiazides, allopurinol, anticonvulsants, NSAIDs, biologics/ICI.
- Systemic diseases: SLE, RA, Sjögren, IBD; malignancy (hematologic > solid).
- Cold-precipitable immune complexes: cryoglobulinemia (often HCV-related).
Clinical Features
- LCV/CSVV: crops of palpable purpura on legs/buttocks; may coalesce; burning/tenderness > itch; can blister or necrose in severe cases.
- Systemic symptoms: arthralgias, low-grade fever; renal (hematuria/proteinuria), GI pain/bleeding, neuropathy suggest systemic involvement.
- IgA vasculitis: palpable purpura plus arthralgia, abdominal pain, renal involvement; more common in children but occurs in adults (more severe kidneys).
- Urticarial vasculitis: wheals last >24 hours, leave bruise/hyperpigmentation; hypocomplementemia may indicate systemic disease.
- cPAN: tender subcutaneous nodules, livedo racemosa, digital ischemia/ulcers; neuropathy.
- AAV: purpura, ulcers, nodules; systemic features (ENT/lung/kidney) are key.
Diagnostic Workup
- Biopsy: perform within 24–48 hours of lesion onset; punch/excisional from fresh purpura for H&E; perilesional for DIF. LCV shows neutrophilic infiltrate with fibrinoid necrosis and leukocytoclasis; DIF can reveal IgA (IgA vasculitis), C3/IgM, or C1q (urticarial vasculitis).
- Basic labs for all suspected vasculitis: CBC, CMP, ESR/CRP, urinalysis (hematuria/proteinuria), creatinine.
- Extended testing based on context: hepatitis B/C, HIV; ANA, complements (C3/C4), rheumatoid factor; cryoglobulins; ANCA (PR3/MPO) if AAV suspected; serum protein electrophoresis if monoclonal gammopathy suspected.
- Imaging/electrodiagnostics for medium-vessel disease or neuropathy as indicated.
Management
- Remove triggers and supportive care
- Discontinue culprit drugs; treat infections.
- Leg elevation, compression (if not ischemic), rest, analgesia; skin care for ulcers.
- Mild cutaneous-limited CSVV
- Often self-limited (weeks). Topical steroids for symptomatic relief; short course NSAIDs if no renal/GI involvement.
- Moderate/severe or recurrent cutaneous disease
- Oral corticosteroids (e.g., prednisone 0.5 mg/kg/day taper).
- Steroid-sparing agents for relapsing disease: colchicine, dapsone (check G6PD), hydroxychloroquine; methotrexate, azathioprine, mycophenolate for refractory cases.
- Systemic vasculitis or organ-threatening disease
- Tailored to subtype:
- IgA vasculitis with nephritis: nephrology co-management; corticosteroids +/- immunosuppressants case-by-case.
- Urticarial vasculitis (hypocomplementemic/systemic): corticosteroids; add dapsone, hydroxychloroquine, azathioprine, mycophenolate, or rituximab for refractory.
- cPAN: corticosteroids; adjunct immunosuppressants (azathioprine, methotrexate, cyclophosphamide) for severe disease; treat underlying infections (e.g., streptococcal).
- AAV with skin/systemic involvement: induction with glucocorticoids plus rituximab or cyclophosphamide per guidelines; PJP prophylaxis; maintenance with rituximab/azathioprine/methotrexate.
Prognosis and Follow-up
- Many cutaneous-limited cases resolve; recurrence common if triggers persist.
- Adult IgA vasculitis has higher renal risk—monitor urinalysis and BP for at least 6–12 months.
- Urticarial vasculitis with hypocomplementemia more likely systemic; monitor lungs, kidneys.
References (recent guidelines and key reviews)
- EULAR recommendations for ANCA-associated vasculitis, 2022–2024.
- Dermatology/rheumatology consensus on cutaneous vasculitis diagnosis and management, 2022–2024.
- ACR/VF guidelines on vasculitis, 2021–2024 updates.
- Reviews on urticarial vasculitis and cryoglobulinemic vasculitis, 2021–2024.