What are the clinical presentations and cutaneous findings of small vessel vasculitis, medium vessel vasculitis, and large vessel vasculitis?

Clinical Presentations and Cutaneous Findings of Vasculitis by Vessel Size

The clinical presentations and cutaneous findings of vasculitis vary distinctly based on vessel size involvement, with small vessel vasculitis typically presenting with palpable purpura, medium vessel vasculitis with nodules and livedo reticularis, and large vessel vasculitis with constitutional symptoms and ischemic manifestations.

Small Vessel Vasculitis

Small vessel vasculitis affects arterioles, capillaries, and venules, with characteristic cutaneous manifestations:

Clinical Presentations:

• Palpable purpura (most common presentation)
• Symmetrically distributed lesions, predominantly on lower extremities
• Petechiae
• Urticarial plaques that persist >24 hours
• Infiltrated erythema
• Vesicles, pustules, or bullae (in severe cases)

Cutaneous Findings:

• Leukocytoclastic vasculitis on histopathology with neutrophilic infiltration
• Fibrinoid necrosis of vessel walls
• Nuclear dust (leukocytoclasia)
• Extravasation of red blood cells
• Endothelial swelling

Specific Types and Their Distinct Features:

• ANCA-Associated Vasculitis (AAV):

  • Granulomatosis with polyangiitis (GPA): Nodules on elbows with histological palisading granuloma 1
  • Microscopic polyangiitis (MPA): Livedo reticularis pattern 1
  • Eosinophilic granulomatosis with polyangiitis (EGPA): Purpura and petechiae with paresthesias on lower extremities 1

• Immune Complex Vasculitis:

  • IgA vasculitis (Henoch-Schönlein purpura): Palpable non-thrombocytopenic purpura 1
  • Cryoglobulinemic vasculitis: Microvascular thrombi and leukocytoclastic vasculitis 1

Medium Vessel Vasculitis

Medium vessel vasculitis affects main visceral arteries and their initial branches:

Clinical Presentations:

• Subcutaneous nodules
• Deep ulcers
• Livedo reticularis/racemosa
• Digital gangrene
• Mononeuritis multiplex
• Abdominal pain (mesenteric involvement)
• Hypertension (renal artery involvement)

Cutaneous Findings:

• Deeper dermal or subcutaneous vessel involvement
• Mixed-cell inflammatory infiltrates in vessel walls
• Fibrinoid necrosis
• Absence of granulomas and giant cells in polyarteritis nodosa 2

Specific Types:

• Polyarteritis Nodosa (PAN):

  • Cutaneous PAN: Vasculitis limited to skin without internal organ involvement 1
  • Systemic PAN: Affects medium and small visceral vessels, particularly renal arteries 2

• Kawasaki Disease:

  • Self-limiting acute necrotizing vasculitis
  • Affects medium and small vessels
  • Common in Asian populations
  • Often involves coronary arteries (15-20% of patients) 2

Large Vessel Vasculitis

Large vessel vasculitis affects the aorta and its main branches:

Clinical Presentations:

• Constitutional symptoms (fever, weight loss, fatigue)
• Claudication of extremities
• Diminished or absent pulses
• Vascular bruits
• Asymmetric blood pressure readings
• Headache, jaw claudication (in GCA)

Cutaneous Findings:

• Less common than in small/medium vessel vasculitis
• Scalp tenderness and necrosis (in GCA)
• Raynaud's phenomenon
• Skin ulceration due to ischemia
• Gangrene in severe cases

Specific Types:

• Giant Cell Arteritis (GCA):

  • Affects older patients (>50 years)
  • Involves supra-aortic vessels, especially extracranial branches of carotid artery 2
  • Less frequent jaw claudication or ischemic symptoms in large-vessel GCA compared to cranial GCA 2

• Takayasu Arteritis (TAK):

  • Affects young women (≤40 years)
  • Involves aorta and main branches, pulmonary and coronary arteries 2
  • Clinical presentation ranges from asymptomatic to nonspecific constitutional symptoms and major ischemic events 2

Diagnostic Approach

Laboratory Testing:

• Complete blood count with differential
• Renal function tests
• Urinalysis with microscopic examination
• Inflammatory markers (ESR, CRP)
• ANCA testing
• Hepatitis B and C serology (especially for PAN)
• Cryoglobulins 3

Imaging Based on Vessel Size:

• Large vessels: CT/CTA, MRI/MRA, or FDG-PET/CT
• Medium vessels: CTA of affected regions (renal, mesenteric, coronary)
• Small vessels: MRI/MRA or FDG-PET/CT 3

Biopsy:

• Gold standard for diagnosis of cutaneous vasculitis 4
• Essential for ANCA-negative cases with compatible clinical presentation 3
• Should extend to subcutis from the most tender, reddish, or purpuric lesional skin 5
• Direct immunofluorescence helps distinguish IgA-associated from IgG/IgM-associated vasculitis 5

Common Pitfalls and Caveats

1. Misdiagnosis of pseudovasculitis: Thrombotic disorders like antiphospholipid syndrome can mimic vasculitis 5

2. Underestimating systemic involvement: Cutaneous manifestations may be the first sign of systemic vasculitis 3

3. Failure to recognize ANCA-negative vasculitis: Approximately 10% of patients with clinical features of small-vessel vasculitis are ANCA-negative 3

4. Delayed diagnosis: Early diagnosis and treatment are essential for improving survival in vasculitis 3

5. Inadequate biopsy: Serial sections are often required to identify the main vasculitic lesion 5

6. Overlooking coexistence of different vessel involvement: Concurrent pan-dermal small-vessel vasculitis and subcutaneous muscular-vessel vasculitis usually indicates connective tissue disease, ANCA-associated vasculitis, Behçet disease, or malignancy-associated vasculitis 5