Venous Leg Ulcer

Venous ulcers are usually large, shallow, painless and situated around the medial or lateral malleoli. They are associated with other signs of venous hypertension such as varicose veins, varicose eczema, haemosiderin pigmentation, atrophy blanche and venous flare. Oedema of the lower leg may be present, and chronic venous stasis can lead to warty hyperplasia of the skin or thickening of the subcutaneous tissues.
Venous ulcers are caused by incompetent valves in the veins of the lower leg, especially in the perforators. These valves allow blood to be squeezed out into the superficial veins when the calf muscles are contracted instead of upwards towards the heart. Dilation of superficial veins occurs (varicosities) and the subsequent raised venous hypertension results in oedema, venous eczema and ulceration. The loss of valves is the result of damage following venous thrombosis. Valves may also become damaged following the venous hypertension that occurs in pregnant women. In some instances, there may be congenital absence of valves.

The prevalence in the UK is 1.5-3 per 1000. It increases with age, and reaches 20 per 1000 in the 80 plus age group.¹

The diagnosis is usually made clinically.

History

The following history may suggest venous ulceration:²

• Pre-existing varicose veins
• Deep vein thrombosis
• Phlebitis
• Previous fracture, trauma, or surgery
• Family history of venous disease
• Symptoms of venous insufficiency:(e.g. pains or heaviness in the legs, aching, itching, swelling, breakdown of the skin surface, pigmentation, eczema)

Features in the history which suggest a non-venous cause include:

• Family history of non-venous ulcers
• History of:heart disease, stroke, transient ischaemic attack
• Diabetes mellitus
• Peripheral vascular disease or intermittent claudication
• Cigarette smoking
• Rheumatoid arthritis.

Examination

80% of all leg ulcers are venous ulcers, and a large shallow relatively painless ulcer with an irregular granulating base in the 'gaiter' region of the leg (between the knee and ankle) is likely to be venous in origin.³ There may be surrounding stasis dermatitis.
Differential diagnosis includes:

• Arterial ulcer - look for reduced pulses in the foot, ankle and possibly femoral artery. These ulcers occur most commonly in areas of poor blood supply, e.g tip of toes or over the tibia, and are typically painful and deep. Other evidence of poor blood supply may include peripheral cyanosis and claudication.
• Neuropathic ulcer - this is painless, deep, often with overlying hyperkeratosis, and occur at sites of loss of nerve supply and recurrent trauma, i.e. heel, metatarsal heads.
• Malignancy - malignant ulcers in this area are rare, but the possibility should not be overlooked. Watch out for an ulcer with a rolled everted edge. Chronic venous ulcers can develop into malignant ones, so any non-healing ulcer should be referred for biopsy.
• Rheumatoid ulcer - these look a bit like arterial ulcers, and are sharp, deep, well-demarcated ulcers with a punched out appearance. They occur typically on the dorsum of foot and calf. and may be slow to heal. Venous ulcers also occur in rheumatoid patients, so the differentiation may be difficult. It is however worthwhile referring suspected rheumatoid ulcers to a rheumatologist, as such ulcers often respond well to a disease modifying anti-rheumatic drug (DMARD).

By the very nature of epidemiology, the patient may be elderly, frail and with reduced mobility, and investigations in these circumstances may be limited. Primary care clinicians are advised to liaise with local community services to see what is available. Skilled nurses may well be able to carry out at least some of these investigations in the community.
SIGN guidance recommends:⁴

• Measurement of Ankle Brachial Pressure Index (ABPI) using Doppler - this is to exclude an arterial ulcer.⁵ A blood pressure cuff is applied to the lower calf muscle just above the ankle. A Doppler ultrasound probe is placed over the dorsalis pedis artery. The maximum cuff pressure at which a pulse can be heard is then recorded. The figure is then expressed as a ratio of the systolic pulse measured at the brachial artery. An index of 0.80 or less suggests significant peripheral arterial disease. In these cases, SIGN recommends referral to a vascular specialist.
• Measurement of the surface area - this gives an indication of rate of healing or failure to progress.
• Swabs for microbiology - this is only necessary if there are clinical signs of infection such as cellulitis.
• Patch testing - if there is associated dermatitis, chronic ulcer patients should be referred for patch testing using what is known as the 'leg ulcer series'. This is a group containing the kind of allergens to which a leg ulcer patient would be exposed - e.g. chemicals contained in leg ulcer dressings.
• Biopsy - if the ulcer has an atypical appearance or fails to heal after twelve weeks of active treatment.

• Graduated compression - before this treatment is tried, diabetes, neuropathy and peripheral vascular disease should be excluded, and pre-existing swelling controlled by bed rest or elevation. The treatment involves applying bandages to the leg, maximising the pressure at the ankle and gaiter area, and reducing the pressure as one goes higher up the leg. This helps to control or reverse venous insufficiency. There are many options available in terms of types of dressing, number of layers and whether to use elasticated or non-elasticated bandages. For uncomplicated venous ulcers, SIGN recommend an elasticated multi-layer dressing (wool padding, dressing to keep padding in place, elasticated bandage, and outer cover).
• Debridement and Cleaning - adherent slough should be debrided and any trapped pus released. Somewhat surprisingly, a randomised study found that cleaning traumatic soft tissue wounds with tap water resulted in a lower rate of infection than if sterile saline was used.
• Dressing - for painless ulcers there is no evidence that hydrocolloidal dressings are superior to simple dry dressings. Pain should raise the question as to whether the ulcer is really venous or whether it is indeed arterial. For those few venous ulcers which are painful, hydrocolloidal or foam dressings should be used.
• Antibiotics - these are not indicated for uninfected ulcers. If there is clinical suspicion of infection (e.g. the presence of cellulitis), a swab should be taken and oral antibiotics instituted. Topical antibiotics can cause sensitivity and there is no place for them, except for metronidazole gel, which may be useful for malodorous ulcers.
• Topical steroids - a moderately potent steroid (e.g. clobetasone) may be helpful in treating surrounding venous (stasis) dermatitis. Persistent dermatitis which fails to respond to treatment suggests an iatrogenically-induced allergy and is an indication for patch testing.

Better results can be expected if the patient is mobile, able to walk, and has no significant co-morbidities.

Referral is indicated in the following situations:

• Diabetes mellitus
• Peripheral arterial disease (ABPI <0.8)
• Rheumatoid ulcer
• Suspicion of malignancy
• Atypical distribution of ulcers
• Dermatitis resistant to topical steroids
• Patients who may benefit from venous surgery or skin grafting
• Failure to progress.

Venous surgery

This is indicated in the following situations:³

• Patient fit for surgery (local anaesthesia if necessary)
• Sufficient mobility to activate calf muscle pump
• Prepared to attend hospital for investigation and surgery
• Obesity controlled (body mass index < 30)
• Superficial venous incompetence: no deep venous incompetence on duplex imaging, or predominantly superficial venous incompetence on ambulatory venous pressures with tourniquet occlusion of the superficial veins.

Pinched skin grafting

This may be indicated in patients with extensive areas of ulceration. This has been done successfully by nurses in the community who have been trained in the technique.³ Bilayer artificial skin used with compression bandaging has also shown to be helpful.⁶

Primary prevention of venous insufficiency

Avoidance of prolonged standing or sitting, control of risk factors (e.g. obesity), and use of compression hosiery when early signs of venous insufficiency (e.g. stasis dermatitis) can all help to prevent the development of ulcers.⁷

Secondary prevention of a recurrent ulcer

• Correctly fitted compression hosiery should be worn for five years after an ulcer.
• Underlying co-morbidities (e.g. diabetes, rheumatoid arthritis) should be managed appropriately.
• Vascular surgery should be considered if the patient fits the criteria (see above).