MODEL RELEASED. Bandaging leg ulcer. District nurse applies a bandage to the leg of an elderly woman patient suffering from leg ulcers. A leg ulcer is an open sore on the leg that fails to heal, usually caused by poor blood supply. Bandaging and dressing ulcers is the only effective treatment. If the ulcer is exuding pus, a wet dressing will be necessary under the bandage. The dressing should be changed only every three to seven days to avoid removing fresh skin from the area. Common causes of ulcers include diabetes, peripheral vascular disease, varicose veins and bed sores. Leg ulcers are more commonly found in elderly patients.