Leg Ulcers

Differential Diagnosis

Common Diagnoses

  • Venous Disease: 70%–80% of Leg Ulcers
  • Peripheral Arterial Disease: About 15% of Leg Ulcers
  • Associated with Systemic Disease: Diabetes (5% of Ulcer Patients), Rheumatoid Arthritis (8%), Vasculitis
  • Gross Oedema Due to Systemic Causes (e.g. CCF, Renal Disease, Osteoarthritis, Severe Obesity, Prolonged Immobility from any Cause)
  • Chronic Infection (e.g. After Trauma, Insect Bite)

Occasional Diagnoses

  • Drug Misuse
  • After Primary Herpes Zoster
  • Primary Malignancy: Squamous Cell Carcinoma, Melanoma, Malignant Change in an Existing Ulcer
  • Secondary Malignancy: Metastases

Rare Diagnoses

  • Tropical Infections
  • AIDS
  • Tuberculosis
  • Systemic Drug Reaction
  • Factitious: Self-Inflicted (Munchausen’s, Personality Disorder)

Ready Reckoner

Key distinguishing features of the most common diagnoses

Venous DiseaseArterial DiseaseSystemic DiseaseOedemaInfection
Venous Eczema/LipodermatosclerosisYesNoPossiblePossibleNo
Weak or Absent Peripheral PulsesNoYesPossiblePossibleNo
Generalised IllnessNoNoYesPossiblePossible
Reduced MobilityPossiblePossiblePossibleYesNo
Identifiable Trigger EventNoNoNoPossiblePossible

Possible Investigations

Likely:FBC, ESR/CRP, TSH, LFTs, U&E, fasting glucose or HbA1c and rheumatoid factor/anti-CCP antibodies, ABPI.

Possible:Swabs for bacteriology, cardiovascular assessment if appropriate.

Small Print:Duplex ultrasound.

  • FBC, ESR/CRP, CRP, TSH, LFTs, U&E, fasting glucose or HbA1c and rheumatoid factor/ anti-CCP antibodies as a basic screen for systemic causes and background disease.
  • Swabs for bacteriology are only useful if there is clinical evidence of viable tissue infection, e.g. cellulitis.
  • Full cardiovascular assessment if any suspicion of arterial insufficiency.
  • Ankle brachial pressure index (ABPI) in both legs by handheld Doppler. Sensitivity of up to 95%; if less than 0.8 assume arterial disease is present. Limited usefulness in patients with microvascular disease, e.g. RA, DM, systemic vasculitis; calcified arteries may cause spuriously high ABPI.
  • Specialist: Duplex ultrasound is the investigation of choice to assess arterial and venous insufficiency.

Top Tips

  • Be systematic in the clinical notes: Describe the edge (e.g. rolled, punched-out), base (e.g. sloughy, necrotic, granulating), location, morphology and surface area (serial measurements of surface area of an ulcer are a good index of healing).
  • Palpation of peripheral pulses is not a reliable guide to arterial sufficiency. Use the ABPI.
  • Lipodermatosclerosis is a red or brown patch of skin on the lower leg, usually on the medial side, just above the ankle. This and venous eczema are indications of superficial venous valve failure, even in the absence of varicose veins. They may represent disease amenable to surgery, so refer for a vascular opinion.
  • Deep ulcers involving deep fascia, tendon, periosteum or bone may well have an arterial component.
  • Mixed ulcer aetiology may confuse the clinical picture and make treatment choices harder. Refer for a specialist opinion if in any doubt.
  • More than 50% of leg ulcer patients are sensitive to one or more allergens, including lanolin, topical antibiotics, cetyl stearyl alcohols, balsam of Peru and parabens. These may contribute to non-healing and cause discomfort to the patient. Refer the patient for patch testing if dermatitis is associated with a leg ulcer.
  • Topical antibiotics do not contribute to healing and are frequent sensitisers – avoid using them.

Red Flags

  • Pain from an ulcer is most frequently associated with an arterial aetiology.
  • Beware neoplastic change in an existing ulcer. This is rare, but not to be missed. Consider referral for biopsy if the ulcer has an atypical appearance or fails to improve with treatment.
  • Compression bandaging is dangerous in diabetes and arterial insufficiency. Do not prescribe it until they are ruled out. If in doubt about ABPI, refer for a vascular opinion.

Published: 2nd August 2022 Updated: 10th April 2024

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