Leg ulcers

What is a leg ulcer?

A leg ulcer is a long-lasting sore that takes more than 2 weeks to heal, usually developing on the inside of the leg between the knee and ankle. Most are venous leg ulcers, caused by persistently high pressure in the veins of the leg, which weakens the skin until it breaks down, often after a minor injury.

Symptoms of a leg ulcer

As well as the sore itself, you may notice:

• pain, itching or a heavy, aching feeling in the affected leg
• swollen ankles
• discoloured or darkened skin around the ulcer
• hardened skin around the ulcer, which can make your leg feel hard
• flaky, scaly, itchy skin, known as varicose eczema
• swollen, enlarged veins (varicose veins) or tiny veins around your ankle
• a foul-smelling discharge from the ulcer.

See a doctor as soon as possible if you notice signs of infection, such as worsening pain, a green or unpleasant discharge, redness and swelling around the ulcer (which can be harder to see on black or brown skin), a high temperature, or an unpleasant smell.

Causes of leg ulcers and who is at risk

Venous leg ulcers happen when the valves inside your leg veins stop closing properly. This causes blood flow backwards and pressure build up, pushing fluid out of the vein and into the surrounding skin. Over time, this damages and weakens the skin, and a minor knock or scratch is then enough to break it and form an ulcer that struggles to heal.

Your veins can be weakened by:

• a previous injury, fracture, or operation on your leg, such as a hip or knee replacement
• a previous blood clot (deep vein thrombosis)
• extra weight on your abdomen, from obesity or pregnancy
• your veins naturally weakening as you get older.

You're also more at risk if you have varicose veins, or if a condition such as osteoarthritis, paralysis, or obesity makes it difficult for you to move around. Venous leg ulcers affect around 1 in 500 people in the UK, rising to about 1 in 50 people over 80, and if you've had one before, you're more likely to get another in the same leg.

Are there different types of leg ulcer?

Yes. Most leg ulcers, around 70–80%, are venous leg ulcers, but other, less common types include:

• arterial leg ulcers, caused by poor blood circulation in the arteries rather than the veins
• diabetic leg ulcers, caused by the high blood sugar associated with diabetes
• vasculitic leg ulcers, linked to inflammatory conditions such as rheumatoid arthritis or lupus
• traumatic leg ulcers, caused by an injury to the leg
• malignant leg ulcers, caused by a skin tumour.

It's important to know which type you have, since arterial ulcers can't be treated with the compression therapy used for venous ulcers, and around 10–20% of ulcers involve a mix of venous and arterial disease.

How leg ulcers are diagnosed

Your GP or nurse will ask about your medical history and examine your leg, both standing and lying down, looking for swelling, varicose veins, and changes to the skin's colour, temperature or shape.

They'll usually also carry out a Doppler or ankle brachial pressure index (ABPI) test, using a handheld ultrasound device to compare the blood pressure in your arm and ankle. This checks how well blood is flowing through the arteries in your leg, since it's not safe to use compression treatment if your arterial blood supply is poor. You may also need a blood test.

How leg ulcers are treated

Non-surgical treatment

Compression, using bandages or stockings, is the main treatment for venous leg ulcers, and is essential for helping blood flow back up the leg while you sit, stand or walk. This must be fitted and applied by a trained healthcare professional and is usually changed 1–3 times a week alongside your wound dressing.

Compression can be uncomfortable at first, so you may be prescribed paracetamol or another painkiller; this usually eases as the ulcer starts to heal. Other things that can help include:

• keeping your leg raised, with your ankle above your hip, whenever you can
• staying as active as possible, including regular walking and ankle exercises, since moving your foot and ankle helps squeeze blood back up through your calf muscles
• avoiding long-distance travel until your ulcer has healed. Antibiotics may be used if your ulcer becomes infected, though they don't help the ulcer itself to heal. With appropriate compression treatment, most venous leg ulcers heal within 6 months, and up to 70% can heal within 3 months when properly managed, though some take longer and a small number never heal.

Surgical treatment

Surgery to treat the damaged vein underneath the ulcer can improve healing and reduce the chance of the ulcer coming back. This might involve removing the affected vein, or sealing it using heat, ultrasound, or a foam solution. A vascular surgeon can advise you on the best option after scanning your veins to see which one is affected.

Unless the underlying cause, such as a damaged vein, is treated, there's a high risk of the ulcer returning even after it's healed.

When to see a doctor

See your GP as soon as you notice a leg ulcer, since it's very unlikely to heal on its own and needs specialist treatment. Contact your GP or leg ulcer specialist urgently if you've already been diagnosed with a leg ulcer and develop signs of infection.

It's also worth booking an appointment if you've had a leg ulcer before and feel like another one may be starting, even if the skin hasn't broken yet.