Stasis dermatitis is inflammation on the lower legs resulting from the pooling of blood and fluid.
Stasis dermatitis tends to occur in people who have varicose veins (dilated, twisted veins) and swelling (edema) of the lower legs who then develop chronic venous insufficiency. Chronic venous insufficiency is damage to leg veins that prevents blood from flowing normally, causing stasis dermatitis. Stasis dermatitis usually occurs on the ankles but may spread upward to the knees.
At first, the skin becomes reddened and mildly scaly. Over several weeks or months, the skin turns dark brown. Eventually, areas of the skin may break down and form an open sore (ulcer), typically near the ankle. Ulcers sometimes become infected with bacteria. Stasis dermatitis makes the legs feel itchy and swollen, but not painful. Ulcers are usually painful.
The skin may become hard, thick, painful, and tender. This complication is called lipodermatosclerosis.
Doctors diagnose stasis dermatitis in people who have the characteristic skin changes and chronic venous insufficiency, but sometimes more extensive evaluation and imaging tests (such as ultrasonography) are needed.
Long-term treatment is aimed at treating chronic venous insufficiency by keeping blood from pooling in the veins around the ankles. When sitting, the person should elevate the legs above the level of the heart. Properly fitted prescription support hose (compression stockings) also prevent pooling of blood and decrease swelling. Department store "support" stockings are not usually adequate.
For dermatitis that has started recently, soothing compresses, such as gauze pads soaked in tap water or aluminum acetate (Burow solution), may make the skin feel better and can help prevent infection by keeping the skin clean. If the disorder worsens, as evidenced by increased warmth, redness, small ulcers, or pus, a more absorbent dressing can be used.
Corticosteroid creams or ointments are also helpful and are often combined with zinc oxide paste and applied in a thin layer. Corticosteroids should not be applied directly to an ulcer because this will interfere with healing.
When a person has large or extensive ulcers, special moisture-containing hydrocolloid or hydrogel dressings may be used. Antibiotics are used only when the skin is already infected. Sometimes, skin from elsewhere on the body may be grafted to cover very large ulcers.
Some people may need an Unna paste boot, which is a woven stretch wrap filled with a gelatin paste that contains zinc. The wrap is applied to the ankle and lower leg where it hardens, similar to but softer than a cast. The boot limits swelling and helps protect the skin from irritation, and the paste helps heal the skin. At first the boot is changed every 2 or 3 days, but later it is left on for a week at a time. After the ulcer heals, an elastic support should be applied before the person rises in the morning. Regardless of the dressing used, reduction of swelling (usually with compression) is essential for healing.
In stasis dermatitis, the skin is easily irritated. Antibiotic creams, first-aid (anesthetic) creams, alcohol, witch hazel, lanolin, or other chemicals should not be used because they can make the disorder worse.