Infected Venous Leg Ulcer

Infected venous leg ulcer is a chronic leg ulcer from venous hypertension that has developed bacterial infection (local infection, cellulitis or deeper infection). All chronic ulcers are colonised, so infection is diagnosed clinically rather than by swab.

• Organisms: Staphylococcus aureus, beta haemolytic streptococci, Pseudomonas aeruginosa, anaerobes, enterococci.
• Risk factors: large and long standing ulcer, diabetes, poor nutrition, immobility, peripheral arterial disease, HIV, steroid use, obesity.

Shallow irregular ulcer in the gaiter area (medial malleolus) with surrounding oedema, lipodermatosclerosis and haemosiderin staining; signs of infection are increasing pain, malodour, purulent or increased exudate, friable granulation, spreading erythema, warmth, fever, delayed healing.

• Differential diagnosis: arterial ulcer, mixed ulcer, diabetic ulcer, pyoderma gangrenosum, vasculitic ulcer, sickle cell ulcer, tropical ulcer, malignant ulcer (squamous cell carcinoma, Marjolin), pressure ulcer, calciphylaxis, contact dermatitis.
• Complications: cellulitis, lymphangitis, osteomyelitis, septicaemia, deep vein thrombosis, contact sensitisation, chronic non healing, malignant transformation, amputation.

Clinical, with vascular assessment.

• Ankle brachial index (to exclude arterial disease before compression); duplex ultrasound of the veins.
• Deep swab or tissue culture after cleansing only if clinically infected; blood cultures if febrile; full blood count, CRP, glucose, albumin, creatinine.
• Radiograph if bone is probed; biopsy of the edge for ulcers present beyond 3 months or atypical.

Treat infection, then restore venous return with compression.

• Supportive: elevate legs above heart level when resting, cleanse with saline or potable water, debride slough, exercise (calf pump), weight loss, nutrition (protein 1.25 to 1.5 g/kg/day), glycaemic control, stop smoking, analgesia (paracetamol 1 g; avoid long term NSAIDs).
• Pharmacological: local infection: iodine or silver impregnated dressings for 2 weeks; avoid topical antibiotics and sensitisers. Cellulitis: flucloxacillin 500 mg to 1 g four times daily for 7 to 14 days (penicillin allergy: clindamycin 300 to 450 mg four times daily, or doxycycline 100 mg twice daily). Severe: benzylpenicillin 1.2 to 2.4 g IV every 6 hours with flucloxacillin 1 to 2 g IV every 6 hours, adding vancomycin 15 to 20 mg/kg IV every 12 hours for MRSA; Pseudomonas: ciprofloxacin 500 to 750 mg twice daily. Pentoxifylline 400 mg three times daily and aspirin 75 mg daily as adjuncts. Tetanus toxoid if needed.
• Procedures: compression bandaging at 30 to 40 mmHg once infection is controlled and ankle brachial index is 0.8 or more; endovenous ablation or surgery for superficial reflux; skin grafting for large or slow healing ulcers; debridement under anaesthesia.
• Special groups: pregnancy, avoid pentoxifylline and use compression; diabetes, check feet and perfusion; sickle cell disease, transfusion and ulcer care; HIV, antiretroviral therapy and nutrition.
• Red flags: fever, rigors, rapidly spreading erythema, ankle brachial index under 0.5, exposed bone, foul purulent discharge, necrosis, ulcer not healing after 12 weeks.
• Follow-up: weekly dressing review; measure area; biopsy if non healing at 3 months; lifelong compression and elevation to prevent recurrence.