How do I differentiate arterial from venous ulcers on physical examination (PE)?

Differentiating Arterial from Venous Ulcers on Physical Examination

Venous ulcers are located around the medial malleolus with irregular borders and granulation tissue, while arterial ulcers present with intense pain, well-demarcated borders, and a dry appearance on the distal extremities. 1

Location and Appearance

Venous ulcers:

• Located around the medial malleolus (gaiter area) 1
• Irregular but well-defined borders 1
• Base contains granulation tissue 1
• Shallow depth with exudate 2
• Often located over bony prominences 2

Arterial ulcers:

• Located on distal extremities (toes, feet, lateral malleolus) 3, 4
• Well-demarcated, "punched-out" borders 1
• Dry appearance with minimal or no granulation tissue 1
• Pale or cyanotic surrounding skin 1

Pain Characteristics

Venous ulcers:

• Generally less painful 1
• Pain improves with leg elevation 2

Arterial ulcers:

• Intense pain, especially at rest 1
• Associated with claudication (pain while walking) 3, 4
• Rest pain that worsens with leg elevation 3

Associated Physical Findings

Venous ulcers:

• Edema that worsens at end of day 5
• Varicose veins 2
• Venous dermatitis (stasis dermatitis) 2
• Hemosiderin pigmentation (brown discoloration) 2
• Lipodermatosclerosis (hardened, indurated skin) 2
• Atrophie blanche (white scarring) 2
• Inverted champagne-bottle deformity of lower leg 2

Arterial ulcers:

• Absent or diminished pedal pulses 6, 4
• Cool extremity 6
• Pallor on elevation, rubor on dependency 4
• Hair loss on affected limb 4
• Thickened, dystrophic toenails 4
• Femoral bruits 6
• Slow venous filling time 6

Critical Diagnostic Maneuvers

Pulse palpation is essential - absent foot pulses strongly suggest arterial disease 6. However, palpable pulses do not exclude significant ischemia 6.

Ankle-Brachial Index (ABI) measurement:

• ABI <0.9 indicates peripheral arterial disease 6, 1
• ABI 0.9-1.3 largely excludes arterial disease 6
• ABI <0.5 or ankle pressure <50 mmHg indicates severe ischemia requiring urgent revascularization 6, 1
• ABI ≥1.3 suggests medial arterial calcification (common in diabetes) and requires alternative testing 6

Alternative bedside tests when ABI is unreliable:

• Triphasic pedal Doppler arterial waveforms exclude significant arterial disease 6
• Toe-brachial index ≥0.75 excludes arterial disease 6

Common Pitfalls

Mixed arterial-venous disease occurs in 16% of patients with venous ulcers 6, 5. Failure to identify arterial disease can lead to inappropriate compression therapy, which may worsen ischemia 5.

In diabetic patients, neuropathy may mask pain symptoms and cause medial arterial calcification, making ABI unreliable 6. Consider toe pressures or Doppler waveforms in this population 6.

Clinical examination alone is inadequate - up to 50% of patients with foot ulcers have peripheral arterial disease that requires objective vascular testing 6. Always perform ABI or Doppler assessment in all patients with leg ulcers 6.

Immediate Action Required

For arterial ulcers with toe pressure <30 mmHg or ankle pressure <50 mmHg, urgent vascular imaging and revascularization should be considered 6, 1. Without adequate revascularization, arterial ulcers have high amputation risk 1.