What is lower extremity vasculitis?

Lower Extremity Vasculitis

Lower extremity vasculitis is an inflammatory process affecting blood vessel walls in the legs, leading to vessel damage, compromise, or destruction, resulting in hemorrhagic and ischemic events that can cause significant morbidity and mortality if left untreated. 1

Classification and Types

Vasculitis can be classified based on the size of vessels affected:

• Large vessel vasculitis

  • Giant cell arteritis (affects aorta and its first/second-order branches) 1
  • Takayasu arteritis

• Medium vessel vasculitis

  • Polyarteritis nodosa (targets medium-sized muscular arteries) 1
  • Buerger's disease (nonatherosclerotic inflammatory vasculitis affecting small and medium-sized distal arteries, strongly associated with tobacco use) 1

• Small vessel vasculitis

  • Leukocytoclastic vasculitis (most common cutaneous form)
  • Henoch-Schönlein purpura (IgA-associated vasculitis)
  • Microscopic polyangiitis
  • ANCA-associated vasculitis (Wegener's granulomatosis, Churg-Strauss syndrome)

Vasculitis can also be categorized as:

• Primary: idiopathic, occurring independently
• Secondary: associated with underlying conditions such as connective tissue diseases, infections, adverse drug reactions, or malignancies 1, 2

Clinical Presentation

Lower extremity vasculitis typically manifests as:

• Cutaneous signs:

  • Palpable purpura (most common)
  • Infiltrated erythema
  • Nodular erythema
  • Livedo racemosa (reticular pattern)
  • Deep ulcers
  • Digital gangrene 2

• Systemic symptoms may include:

  • Fever
  • Weight loss
  • Fatigue
  • Myalgias
  • Arthralgias

Diagnosis

Diagnosis of lower extremity vasculitis requires:

1. Clinical examination:

   • Comprehensive pulse examination
   • Blood pressure measurement in both arms
   • Auscultation for femoral bruits
   • Assessment of skin color, temperature, hair loss, trophic changes, and ulcerations 1

2. Laboratory tests:

   • Complete blood count
   • Inflammatory markers (ESR, CRP)
   • Renal and liver function tests
   • Urinalysis
   • Autoimmune markers (ANA, ANCA, RF)
   • Cryoglobulins
   • Antiphospholipid antibodies 1

3. Imaging studies:

   • Ankle-brachial index
   • Duplex ultrasound
   • CT angiography
   • MR angiography 1

4. Biopsy:

   • Tissue biopsy is essential for definitive diagnosis
   • Should be taken from the most tender, reddish, or purpuric lesional skin
   • Should extend to the subcutis
   • Serial sections may be required to identify the main vasculitic lesion 2
   • Direct immunofluorescence helps distinguish IgA-associated vasculitis from IgG/IgM-associated forms 2

Differential Diagnosis

Lower extremity vasculitis must be distinguished from:

• Atherosclerotic peripheral arterial disease
• Deep vein thrombosis
• Thrombotic disorders (antiphospholipid syndrome)
• Embolic disease
• Fibromuscular dysplasia
• Physiological entrapment syndromes
• Cystic adventitial disease 3, 1

Treatment and Management

Treatment depends on the specific type of vasculitis, its severity, and organ involvement:

1. General measures:

   • Leg elevation
   • Avoidance of prolonged standing
   • Smoking cessation 1, 2

2. For mild disease:

   • NSAIDs
   • Antihistamines
   • Aspirin 2, 4

3. For mild recurrent or persistent disease:

   • Colchicine
   • Dapsone (first-choice agents) 1, 2, 4

4. For severe cutaneous disease:

   • Systemic corticosteroids
   • Immunosuppressants (azathioprine, methotrexate, cyclophosphamide) 2, 4

5. For systemic vasculitis:

   • Combination of corticosteroids and cyclophosphamide 2, 5

6. For refractory cases:

   • Plasmapheresis
   • Intravenous immunoglobulin
   • Biologic therapies (TNF-alpha inhibitors like infliximab, anti-B-cell antibodies like rituximab) 2, 4

7. Management of complications:

   • Antiplatelet therapy for thrombotic risk
   • Antibiotics for infected ulcerations
   • Wound care for ulcerations
   • Pain management 1

Prognosis and Pitfalls

Common pitfalls in managing lower extremity vasculitis include:

• Delayed diagnosis
• Inadequate biopsy
• Failure to distinguish vasculitis from pseudovasculitis
• Underestimating cardiovascular risk
• Focusing only on leg symptoms while missing systemic involvement 1

Early diagnosis and appropriate treatment are crucial to prevent permanent vessel damage, tissue loss, and potential mortality.