A venous leg ulcer can develop after a minor injury if there's a problem with the circulation of blood in your leg veins. This happens when the pressure inside the veins increases.

This constant high pressure can gradually damage the tiny blood vessels in your skin and make it fragile.

As a result, your skin can easily break and form an ulcer after a knock or scratch.

Unless you have treatment to improve the circulation in your legs, the ulcer may not heal.

Find out how venous leg ulcers are treated

A number of factors can increase your risk of developing a venous leg ulcer, including:

• obesity or being overweight – this increases the pressure in the leg veins
• if you have difficulty walking – this can weaken the calf muscles, which can affect circulation in the leg veins
• previous deep vein thrombosis (DVT) – blood clots that develop in the leg can damage valves in the veins
• varicose veins – swollen and enlarged veins caused by malfunctioning valves
• previous injury to the leg, such as a broken or fractured bone, which may cause DVT or affect your walking
• previous surgery to the leg, such as a hip replacement or knee replacement, which can prevent you moving about
• increasing age – people find it harder to move around as they get older, particularly if they suffer from arthritis