Foot Ulcers

Medically Reviewed By William C. Lloyd III, MD, FACS
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Very simply, a foot ulcer is an open sore on the foot that won’t heal. Left untreated, ulcers turn from shallow sores to deep sores that reach past the skin into the flesh underneath. Complications of foot ulcers include infection, which can spread to the skin, bone and blood, and foot amputation.

Foot ulcers are a frequent complication of diabetes. In fact, foot ulcers are the most common reason for hospital stays for people with diabetes. If you or someone you know develops foot ulcers but has not been diagnosed with diabetes, a blood test for diabetes is strongly recommended.

Foot ulcers due to diabetes are slow to heal, often taking from weeks to even several months to heal. Worse yet, you may not know you have them, since diabetic ulcers are often painless due to diabetic nerve damage.

Most foot ulcers respond well to treatment, which includes debridement to remove diseased tissue and antibiotics if bacterial infection is present. Surgery may be necessary if the ulcer does not respond to conservative wound therapy.

What are the symptoms of foot ulcers?

Most foot ulcers are located on the side or bottom of the foot—the parts of the foot that carry weight when you are walking or standing— or on the top or tip of a toe, where the toe can rub against shoes. Foot ulcers may also indicate poor circulation in the extremities, which in turn can be a symptom of diabetes.

These open sores can range from a shallow, red crater that only breaks the surface of the skin, to a deep crater that extends through the skin into the flesh below. In extreme cases, foot ulcers may even involve tendons, bones and other deep structures. The round crater can have a border of thickened, callused skin that develops over time.

Left untreated, foot ulcers can become infected and develop into:

  • An abscess, a pocket in the flesh filled with pus

  • A spreading infection of the skin and underlying fat, known as cellulitis

  • A bone infection, known as osteomyelitis

  • Gangrene, an area of dead, darkened body tissue

What causes foot ulcers?

Foot ulcers are caused by reduced circulation to the feet and other extremities due to several underlying health issues, the most common being diabetes. Other possible causes include:

Peripheral neuropathy

Peripheral neuropathy is nerve damage to the extremities, particularly the feet or lower legs. Damaged nerves can no longer feel pain or warn you about issues like tight-fitting shoes that can cause rubbing and trigger a foot ulcer. Peripheral neuropathy is a common condition for people with diabetes.

People with peripheral neuropathy may injure their feet without knowing it and need to inspect their feet daily for injuries. Doctors, caregivers and loved ones can help monitor for foot injuries when caring for elderly people and diabetics with vision problems who may have trouble seeing foot problems.

Circulatory problems

Any illness that decreases circulation to the feet can cause foot ulcers. Without adequate blood supply to the feet, the cells do not get enough oxygen and weaken, making them more vulnerable to injury. Inadequate blood supply also slows tissue's ability to heal. Poor circulation in the leg arteries is called peripheral artery disease. It also causes pain in the leg or buttock during walking. It is caused by atherosclerosis, a disease in which cholesterol builds up inside arteries and reduces blood flow.

Abnormalities in the bones or muscles of the feet

Conditions that distort the normal anatomy of the foot, such as claw feet, foot fractures, and severe arthritis can lead to foot ulcers. This is particularly true if a foot is forced into shoes that do not fit the altered shape.

How are foot ulcers treated?

In most cases, foot ulcers are easy to diagnose. If the sufferer has adequate vision, they can see the sores, or they can feel them with their hands. Patients’ caregivers or doctors can easily diagnose foot ulcers with a simple examination.

To treat foot ulcers, doctors may take one or more actions, some of which depend on the underlying health of the patient.

  • Debridement: Doctors often perform debridement to patients who have good circulation in their feet. Debridement consists of the doctor trimming away diseased tissue and often any nearby callused skin, then applying a protective dressing that needs to be changed once every several days. Doctors may prescribe specialized footwear to relieve pressure on the ulcerated area, or prescribe antibiotics if there is the possibility of an infection.

  • Surgery: Foot ulcers not responding to conservative therapy may require surgery. People with poor circulation may need a procedure or surgery to open one or more blocked arteries in the legs. When possible, doctors try to open the blockage though angioplasty. For more significant blood flow problems, surgery is usually needed to re-route blood flow through the leg using a bypass artery.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Jan 21
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  1. Diabetes — foot ulcers. Medline Plus, U.S. National Library of Medicine.

  2. Leg and Foot Ulcers: Treatment Options. Cleveland Clinic.