Venous leg ulcer: causes, compression treatment and prevention

Healthy leg veins have one-way valves that push blood up towards the heart. The British Association of Dermatologists explains that when those valves are faulty, blood flows backwards and pressure builds inside the veins. That sustained pressure damages tiny blood vessels in the skin, which becomes dry, itchy and inflamed, heals badly and can break down after very little trauma such as a knock or scratch.

Some people are born with weak valves, others damage them through a previous blood clot in a vein, and valves also tend to weaken with age. The leaflet notes the ulcers themselves are not hereditary, though factors that raise the risk, such as poor valves or a tendency to clot, can run in families.

The NHS lists factors that make an ulcer more likely. Many of them share one mechanism: anything that stops the calf muscle pumping blood effectively, or raises pressure in the veins, adds strain to the system.

• Being overweight or obese, which increases pressure in the leg veins.

• Difficulty walking, for example from osteoarthritis, paralysis or a leg injury, which weakens the calf pump.

• A previous deep vein thrombosis, which can damage the valves.

• Varicose veins.

• Previous leg injury such as a fracture, or surgery such as hip or knee replacement that limits movement.

• Increasing age, since mobility often declines.

Before the ulcer appears you may notice swelling and discomfort on standing for long periods. The dermatology leaflet describes brown spots and patches, skin that looks red or blue, and itchy, scaly skin with firm tender areas beneath. The ulcer is an open wound with a bed that may look bumpy, moist and red, or be covered by a yellowish-grey layer, and it often leaks fluid.

The NHS adds that pain, itching and swelling are typical, that skin around the ulcer may be discoloured or hardened and that a foul-smelling discharge can occur. Pain from a venous ulcer usually eases with the leg raised or when compression is applied. The dermatology leaflet warns that severe pain may mean another cause, such as blocked arteries, infection or a clot in a vein, and should be reported to a doctor immediately.

Diagnosis rests mainly on your history and an examination of the leg. A GP or practice nurse will ask about swelling, skin changes and conditions such as diabetes, previous DVT, leg injury or surgery, and will look at the leg standing and lying down because varicose veins show better when upright and the ulcer is easier to inspect lying down. They will also feel the pulses at your ankles.

The most important investigation is a Doppler test. The NHS explains it compares blood pressure in the arteries at the ankle with the arm, to rule out peripheral arterial disease. It matters because compression is the main treatment and it is not safe to apply it when the ankle artery pressures are low. Occasionally a biopsy or blood tests are used to exclude conditions that can look similar, such as vasculitis or diabetes-related changes.

Referral may follow if the diagnosis is unclear or an artery problem is suspected. The NHS names vascular specialists for suspected arterial disease, diabetes ulcer clinics and rheumatologists for ulcers linked to diabetes or rheumatoid arthritis.

Treatment is best delivered by a nurse trained in leg ulcer care. The NHS describes cleaning away debris or dead tissue, washing and drying the ulcer, and applying a simple non-sticky dressing, usually changed 1 to 3 times a week. Over this goes a firm compression bandage, made of 2, 3 or 4 layers, designed to squeeze the leg and encourage blood back towards the heart. Bandages are applied by trained staff and normally changed at the same visits.

Compression can be uncomfortable when first applied to an unhealthy ulcer, and the NHS suggests taking paracetamol or another painkiller prescribed by a GP. If a bandage feels tight in bed, a short walk often helps, but it should be removed or cut off if you get numbness or tingling in the feet or toes, unusual pain in the leg, foot or toes, or toes that become swollen, pale or blue. Keep the leg raised and contact a nurse or doctor as soon as possible.

The dermatology leaflet says bandages are generally used until the ulcer has healed or nearly healed, after which stockings take over. Other measures include emollients for dry skin and a steroid cream for eczema around the ulcer, which can sometimes be a reaction to dressings or creams; lanolin, antibiotic creams and preservatives are common culprits. The NHS says infected ulcers are cleaned and dressed as usual and a 7-day antibiotic course prescribed, and that antibiotics should be kept to short courses because they do not heal ulcers. Signs of infection include more discharge, more pain, redness (harder to see on brown and black skin) and feeling unwell.

Compression works best when the calf muscle is working. Both the NHS and the dermatology leaflet stress activity and elevation as part of treatment, not optional extras.

• Walk regularly, and if mobility is limited move the foot up and down and rotate the ankles.

• Keep the leg raised whenever sitting or lying; the NHS suggests elevating the feet for 30 minutes, 3 to 4 times a day, with toes above hips.

• Avoid long periods of standing or sitting with the feet down, and do not sleep in a chair with the legs hanging.

• Moisturise surrounding skin, avoid scratching, and wear well-fitting, comfortable footwear.

• Stop smoking, moderate alcohol and aim for a balanced diet and healthy weight.

• Wash stockings and bandages as instructed and replace stockings every 3 to 6 months, as they lose their stretch.

Healing the wound is only half the task. The NHS says that unless the underlying cause is addressed the risk of recurrence is high, and that someone who has had an ulcer may develop another in the same leg within months or years. Compression stockings put on when you get up and taken off at night are the most effective single measure, fitted by a nurse so that you can manage them yourself.

For people with severe varicose veins, the NHS notes that treating them, by sealing with radio waves or laser through a thin catheter, or by surgery to repair or remove affected veins, may help prevent swelling and ulcers. Whether that is suitable depends on a vascular assessment. The NHS also mentions local Leg Club groups run by a charitable foundation as a social setting for treatment and peer support.

On the NHS, care usually starts with a GP, practice nurse or community and district nursing team, often with referral to a leg ulcer or tissue viability clinic. Frequent early visits are normal, at least once a week at the start according to the NHS, with fewer once healing is under way.

Private vascular or dermatology assessment can speed up investigation of the veins and, where suitable, vein treatment to reduce recurrence. It is reasonable to ask how dressings, bandage changes and follow-up will be provided afterwards, because a single consultation does not replace regular skilled nursing care.