Venous Ulcers

Venous ulcers are sores that develop after veins in the legs have been damaged. These ulcers penetrate deep into the skin.

Venous ulcers are relatively common among older people. Venous ulcers become infected easily. Occasionally, if a venous ulcer persists for a long time, skin cancer develops at the edge. Some venous ulcers, particularly large ones, never heal. However, with or without treatment, many venous ulcers heal.

Causes

Venous ulcers form when blood flow through the legs is reduced, causing blood to pool in the leg veins. Then, pressure increases in the veins and capillaries (tiny blood vessels that connect arteries and veins). The increased pressure causes fluid to leak from the blood vessels into surrounding tissue, and swelling develops. Eventually, swelling interferes with the movement of oxygen and nutrients from capillaries into the tissues. Tissues are damaged because they lack oxygen and nutrients and because the fluid that has leaked puts pressure on them. As a result, venous ulcers may form.

Any disorder that causes blood to pool in leg veins can cause a venous ulcer. A varicose vein or a vein blocked by a blood clot (deep vein thrombosis) can become damaged, causing blood to pool. Such damage to leg veins is called chronic venous insufficiency. Heart failure can also cause blood to pool in veins.

Symptoms and Diagnosis

One or more ulcers develop on the leg. The outer layers of skin die and are shed (sloughed), exposing deeper tissues. Spots of white scar tissue may develop in the skin around a venous ulcer.

If venous ulcers result from chronic venous insufficiency, the legs are swollen, and the skin is dark reddish brown and very firm (a condition called stasis dermatitis). The skin may itch, and the ulcers are usually very painful.

Infection of the skin (cellulitis) often develops around a venous ulcer. Typically, the infected skin is red, warm, swollen, and tender. Red streaks occasionally appear. Pus or fluid may leak from the ulcer, especially if infection involves tissues below the skin (such as muscle).

The diagnosis is based on the appearance of ulcers and symptoms.

Prevention and Treatment

The goals of prevention and treatment are to reduce leg swelling and reduce the pressure in veins. If swelling is reduced enough, a venous ulcer may never form or may heal on its own. Often, specially designed bandages and pressure stockings help reduce swelling. Elevating the leg whenever possible reduces swelling and pressure in veins. However, elevating the legs continuously can keep a person in bed, causing other problems. Drugs that remove extra fluid from the body (diuretics) are sometimes used to treat swelling due to heart failure. However, diuretics usually do not help reduce leg swelling in people with venous ulcers. Also, they may cause excessive urination, which can lead to dehydration.

If cellulitis or signs of an infection of deeper tissues (such as pus) are present, antibiotics are taken by mouth or given intravenously.

Drugs, such as nonprescription antibiotics, should not be applied directly to the skin of the leg. These drugs can cause allergic reactions that worsen the problem, particularly when the skin is cracked or there is an open sore. A doctor who specializes in ulcers can prescribe safe dressings that are often helpful.

If a venous ulcer is very deep or does not heal, healthy skin taken from another part of the body may be applied (transplanted or grafted) over it. Sometimes skin taken from another person and grown in the laboratory is used.

For deep or severe venous ulcers on the foot or lower part of the leg, a paste may be applied to the foot and leg. The paste hardens and is wrapped with a bandage, forming a soft, castlike boot (Unna boot). With the extra protection provided by the boot, the ulcer can heal more quickly.