Cutaneous vasculitis

Cutaneous vasculitis refers to a group of disorders characterized by inflammation of blood vessels in the skin. This condition results from immune-mediated damage to the vascular endothelium, leading to various clinical manifestations such as palpable purpura, ulcers, nodules, and livedo reticularis. In some cases, it remains confined to the skin, while in others, it serves as a marker of systemic vasculitis affecting vital organs.

Classification of Cutaneous Vasculitis

Cutaneous vasculitis is categorized based on the size of the affected blood vessels. The primary classifications include:

1. Small Vessel Vasculitis

This form involves capillaries, venules, and non-muscular arterioles in the superficial dermis. It is the most common type and includes:

• Cutaneous Small Vessel Vasculitis (CSVV) – Often triggered by infections, medications, or systemic diseases.
• Henoch–Schönlein Purpura (HSP) – An IgA-mediated vasculitis, commonly seen in children.
• Urticarial Vasculitis – Characterized by painful, long-lasting urticarial lesions.
• Cryoglobulinemic Vasculitis – Associated with hepatitis C, leading to immune complex deposition.

2. Medium Vessel Vasculitis

This form affects deeper dermal arterioles and is associated with more severe cutaneous findings such as nodules, ulcers, and digital ischemia. Examples include:

• Polyarteritis Nodosa (PAN) – Affects medium-sized arteries, presenting with painful subcutaneous nodules.
• Kawasaki Disease – A childhood vasculitis that can cause mucocutaneous symptoms and coronary artery complications.

3. Mixed Vessel Vasculitis

This category includes vasculitides affecting both small and medium vessels, often with systemic involvement:

• Microscopic Polyangiitis (MPA) – An ANCA-associated vasculitis with skin and kidney involvement.
• Granulomatosis with Polyangiitis (GPA) – Previously known as Wegener’s granulomatosis, affecting respiratory tract and skin.
• Eosinophilic Granulomatosis with Polyangiitis (EGPA) – Characterized by eosinophilia and asthma.

Pathogenesis of Cutaneous Vasculitis

The underlying mechanism of cutaneous vasculitis is immune-mediated damage to the vessel walls, which can occur due to:

• Immune Complex Deposition – Circulating immune complexes lodge in vessel walls, activating complement and neutrophils, leading to inflammation.
• ANCA-Associated Vasculitis – Autoantibodies directed against neutrophilic enzymes (PR3, MPO) promote neutrophil activation and endothelial injury.
• T-Cell Mediated Responses – Inflammatory cytokines contribute to endothelial dysfunction and vascular leakage.

Clinical Features of Cutaneous Vasculitis

The symptoms vary depending on the size of the affected vessels:

• Small Vessel Vasculitis – Presents with palpable purpura, petechiae, and vesiculobullous lesions.
• Medium Vessel Vasculitis – Features nodules, ulcers, livedo reticularis, and digital infarcts.
• Systemic Symptoms – Fever, myalgia, arthralgia, and malaise may accompany skin lesions in systemic vasculitis.

Diagnosis of Cutaneous Vasculitis

A thorough diagnostic approach is essential to determine the underlying cause and extent of the disease:

1. Clinical Evaluation

• History & Physical Examination – Assess onset, distribution, and associated systemic symptoms.
• Triggers – Identify recent infections, medications, or systemic diseases.

2. Laboratory Tests

• Complete Blood Count (CBC) – Evaluates for anemia, leukocytosis, or eosinophilia.
• Erythrocyte Sedimentation Rate (ESR) & C-Reactive Protein (CRP) – Markers of systemic inflammation.
• Urinalysis – Checks for hematuria or proteinuria indicating renal involvement.
• ANCA Testing – Identifies PR3-ANCA or MPO-ANCA in associated vasculitis.
• Cryoglobulins & Complement Levels – Assesses immune complex disorders.

3. Skin Biopsy

• Histopathology – Demonstrates leukocytoclastic vasculitis, fibrinoid necrosis, and perivascular neutrophilic infiltration.
• Direct Immunofluorescence (DIF) – Detects immune complex deposits in vessel walls.

Treatment of Cutaneous Vasculitis

Management depends on severity, underlying cause, and systemic involvement.

1. General Measures

• Rest & Leg Elevation – Reduces edema and promotes healing.
• Avoidance of Triggers – Discontinue offending drugs or treat infections.

2. Pharmacological Treatment

Mild Cases

• Antihistamines – Control pruritus and urticaria.
• NSAIDs – Reduce inflammation and pain.

Moderate to Severe Cases

• Corticosteroids – Prednisone is commonly used for significant inflammation.
• Colchicine – Effective in small vessel vasculitis and leukocytoclastic vasculitis.
• Dapsone – Useful for chronic, relapsing vasculitis.

Severe or Systemic Involvement

• Immunosuppressants – Azathioprine, methotrexate, or mycophenolate mofetil.
• Biologic Agents – Rituximab for ANCA-associated vasculitis.
• Plasmapheresis – Considered in life-threatening ANCA vasculitis.

Prognosis and Complications

The prognosis of cutaneous vasculitis varies:

• Skin-Limited Disease – Generally self-limiting, resolving within weeks.
• Chronic or Relapsing Disease – May require long-term immunosuppression.
• Systemic Vasculitis – Can lead to renal, pulmonary, or neurological complications if untreated.

Early diagnosis and appropriate management improve patient outcomes and reduce morbidity.

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