Slow-healing wounds: why they happen, what to do and when to get help

Most cuts and grazes close up within days or a couple of weeks. A wound that has not shown signs of healing after about two weeks, or that heals and then breaks down again, is described as chronic or non-healing. The NHS uses the same time frame for leg ulcers, which it defines as long-lasting sores that take more than 2 weeks to heal.

The wound itself is rarely the whole story. A wound heals slowly when something is interfering with the blood supply, the skin or the surrounding tissue. Identifying that underlying cause is the most important part of treatment, because a dressing alone cannot make up for poor circulation or constant pressure.

Venous problems are the commonest. The NHS says venous leg ulcers can develop after a minor injury if persistently high pressure in the veins of the legs has weakened the skin. They usually appear on the inside of the leg between the knee and the ankle. You are more at risk if you have had a deep vein thrombosis, have varicose veins, or find it difficult to walk because of osteoarthritis, a leg injury, obesity or paralysis.

Arterial disease is a second route. The NHS lists ulcers (open sores) on the feet and legs that do not heal among the symptoms of peripheral arterial disease, and describes critical limb ischaemia as a more severe stage with wounds and ulcers that do not heal and, in the worst cases, gangrene.

Diabetes is a third. The NHS says diabetes can cause nerve damage and foot problems, and that diabetic leg ulcers are caused by the high blood sugar associated with diabetes. Reduced feeling in the feet means small injuries may go unnoticed for days.

Finally, pressure and friction damage the skin directly. The NHS says pressure ulcers usually form on bony parts of the body such as the heels, elbows, hips and tailbone, and are more likely if you have problems moving, have been seriously ill or recently had surgery, are underweight, have fragile skin or poor circulation, or have problems feeling pain.

An infected wound can worsen quickly and needs treatment. For a leg ulcer, the NHS says a large amount of discharge, more pain and redness around the ulcer, together with feeling unwell, are signs of infection and you should contact your GP or leg ulcer specialist as soon as possible. Redness may be harder to see on black or brown skin.

For pressure ulcers, the NHS says to ask for an urgent GP appointment or get help from NHS 111 if the skin is hot, swollen or red (blue or purple on brown or black skin), if pus is coming from the ulcer, if there is a high temperature, or if there is severe pain or pain that is getting worse.

For circulation problems, the NHS says that if you think you are developing symptoms of critical limb ischaemia, such as severe burning pain in the legs and feet at rest, non-healing wounds, or skin turning cold, numb, red and then black, you should contact a GP immediately. If you cannot get hold of a GP, use NHS 111, and call 999 or go to A&E if you feel acutely unwell or the skin of a limb is changing colour rapidly.

See a GP if a sore has not healed within about two weeks. The NHS says your GP will examine your leg and may carry out additional tests to rule out other conditions. In practice, assessment usually includes checking the pulses in the feet, measuring blood pressure in the ankle compared with the arm to judge arterial flow, looking at the veins, checking blood sugar and asking about previous clots, smoking and mobility.

This matters because the safe treatment differs by cause. Compression, which is the mainstay for venous ulcers, is not appropriate if the arteries are significantly narrowed, so the arterial supply should be checked before strong compression is applied. The NHS also says a venous leg ulcer is treated by a healthcare professional trained in compression therapy, usually a practice or district nurse.

Any ulcer that looks unusual, grows, bleeds easily or fails to improve with appropriate care may need a biopsy to exclude skin cancer, which the NHS lists as a cause of malignant leg ulcers.

Treatment follows the cause. For venous ulcers the NHS describes cleaning and dressing the wound, which is usually changed 1 to 3 times a week, and a firm compression bandage to improve blood flow in the leg. Putting on a bandage is a skilled procedure and should be done by trained staff. A simple non-sticky dressing is normally used. If the compression bandage causes numbness or tingling, unusual pain, or swollen toes that look pale or blue, it should be removed and the doctor or nurse contacted as soon as possible.

For pressure ulcers the NHS says changing position and moving regularly is important to relieve pressure and stop new ones forming, alongside specially designed mattresses and cushions, dressings, creams and ointments, and antibiotics if infected. If a pressure ulcer is severe or other treatments have not worked, surgery to clean and close the ulcer may be needed.

For arterial and diabetic ulcers, treatment centres on improving blood supply and blood sugar control and protecting the foot, usually with specialist teams. These ulcers should not be managed at home without assessment.

The NHS suggests several practical steps for venous ulcers: keep active by walking regularly, elevate the affected leg whenever sitting or lying down, exercise the legs by moving the feet up and down and rotating the ankles, lose weight if overweight, stop smoking and moderate alcohol. It also says to avoid injuring the leg and to wear comfortable, well-fitting footwear.

Recurrence is common. The NHS says that once you have had a venous leg ulcer another can develop within months or years, and that the most effective way to prevent this is to wear compression stockings at all times when out of bed. For pressure ulcers, the NHS advises checking the skin every day, changing position regularly, staying active if possible, eating a balanced diet and not smoking.

If you care for someone who is at risk, the NHS says a GP can be asked for a risk assessment so the care team can make a plan to prevent pressure ulcers.

Wound care in the NHS is usually led by practice or district nurses, with referral to tissue viability nurses, vascular surgeons, podiatrists or diabetic foot teams when needed. Services vary between areas, and some people wait for specialist vascular or diabetic foot assessment.

Some people choose to see a private podiatrist, wound-care nurse or vascular specialist for quicker access or additional appointments. The principles of care are the same: the cause needs to be found and treated, the dressing and compression need to suit that cause, and any change in the wound should be shared with whoever coordinates your care so that treatments are not duplicated or conflicting.