Occur due to pooling of blood and waste products in the skin secondary to venous insufficiency

Aetiology:

• Most are due to venous HTN, secondary to chronic venous insufficiency
  • Other causes - calf pump dysfunction

Pathophysiology:

• Venous incompetence or venous outflow obstruction leads to impaired venous return - venous hypertension - trapping’ WBCs in capillaries and formation of a fibrin cuff around the vessel hinders O2 transportation to tissues
• WBCs activate releasing inflammatory mediators = resultant tissue injury, poor healing and necrosis

Typically seen above the medial malleolus

Risk factors:

• Increasing age
• pregnancy
• obesity/physical inactivity
• severe leg injury or trayma

Features

• Are associated with chronic venous changes, such as hyperpigmentation, venous eczema and lipodermatosclerosis
• Occur after a minor injury to the leg
• Are larger and more superficial than arterial ulcers
• Have irregular, gently sloping border
• Are more likely to bleed