Definition and Overview

Diabetic foot ulcers are open sores that often form on the side or bottom of the foot. They are very common in patients with type 1 or type 2 diabetes and they can take a lot of time to heal. The condition is one of the most common reasons for hospital stays for diabetic patients whose body’s ability to heal wound properly is impaired. Because the wounds are slow to heal, their risk of getting infected is very high. This infection can spread to deep tissues, bones, and tendons. In severe cases, a part of the foot or leg is amputated to stop the infection from spreading further.

Diabetic foot ulcers commonly form under the big toes or balls of the feet. They look like a shallow red crater on the surface of the skin. Most diabetic people do not notice them because they also commonly suffer from nerve damage (diabetic neuropathy). This prevents them from feeling pain and sensation.

Causes of Condition

Diabetes has several complications that can increase a patient’s risk of foot ulcer. These include nerve damage (peripheral neuropathy) and circulatory problems. When the nerves in the lower extremities are damaged, the patient’s feet feel numb. They do not feel pain or sensation even if they stepped on a sharp object or if their foot becomes wounded and bleeds. Unless they check their feet and legs for injury on a daily basis, they may not know that they have ulcers until the infection spreads to other parts of their foot.

Another complication of uncontrolled diabetes is a circulatory problem. This causes some parts of the body not to receive enough blood supply. When this happens, cells become deprived of oxygen. Poor circulation in the leg arteries (peripheral artery disease) makes the feet more vulnerable to injury.

Other factors that can increase the risk of diabetic foot ulcers are:

  • High blood pressure

  • High cholesterol levels

  • Obesity - Being overweight puts more pressure on the feet especially when a person is standing up or walking

  • Sedentary lifestyle

  • Smoking - Smoking affects blood circulation, which impairs the body’s ability to heal itself

  • Poorly fitted shoes

  • Poor hygiene

  • Foot deformity

  • Not wearing shoes

Key Symptoms

A foot ulcer is an open sore that is usually found on the ball of the foot or tip of a toe. It looks like an inflamed crater surrounded by a thickened skin. If the ulcer is very deep, tendons and bones may also show. Abscess is also often present. Other symptoms are:

  • Difficulty walking

  • Feet discolouration

  • Skin redness

  • Swelling

  • Fever

  • Foul smelling discharge

  • Pain

  • Blisters

Who to See and Types of Treatments Available

Doctors perform many different tests to diagnose diabetic foot ulcer. Their goal is to check:

  • The severity of the ulcer

  • If there is an infection

  • Which structures are infected (such as bones and tendons)

  • How well the blood flows to the feet

  • If the patient has other problems that impair their body’s ability to heal wounds

  • If the patient can feel sensation in his feet

These tests include:

  • Physical exam

  • Ankle-brachial pressure

  • Blood glucose and glycohemoglobin test

  • Complete blood count

  • Doppler ultrasound

  • Imaging tests, including x-ray, computed tomography (CT) scan, and magnetic resonance imaging (MRI)

  • Wound culture

Treatment

If blood circulation to the foot is good and the infection has not spread to the bones or tendons, the treatment will involve removing dead skin and tissue (debridement). For this procedure, the doctor will:

  • Clean and disinfect the wound

  • Check the wound for any foreign material or object

  • Cut away dead tissue

  • Remove callused skin surrounding the wound

  • Use skin graft to close the wound, if it is too big

  • Cover the wound with dressing

If the affected foot is not getting enough blood supply, the doctor makes sure that the blood vessels are not blocked. If they are, a procedure called angioplasty is performed. It aims to widen the blood vessel to allow more blood to flow. Another option is a procedure wherein the blood flow is re-routed to bypass the blocked portion of the blood vessel.

Following treatment, the doctor or nurse will:

  • Teach the patient about proper wound care to prevent infection

  • Prescribe antibiotics that the patient may need to take up to six weeks

  • Instruct the patient not to put constant pressure on the ulcer while it is healing. In some cases, they are advised to use a wheelchair until their wound is completely healed.

  • Instruct the patient to properly monitor and control their blood glucose level

  • Advise the patient to quit smoking

Prevention

It is very important for patients with diabetes to prevent an ulcer from developing because they can be very difficult to treat. Their complications can also be very serious. To minimise their risk, a patient must:

  • Avoid wearing tight stockings as this can prevent normal blood flow to the feet

  • Ensure that their feet are clean all the time. They must be washed on a daily basis. They must also be kept dry especially before wearing socks and shoes.

  • Exercise at least one hour per day, five days a week. This helps improve blood circulation.

  • Make it a habit to check the feet everyday for cuts or wounds

  • Moisturise the feet on a daily basis. Dry skin is more prone to ulcers.

  • Never wear ill-fitting shoes

  • Have their feet checked by a doctor at least once a year

References:

  • Standards of medical care in diabetes - 2016: summary of revisions. Diabetes Care. 2016;39:S4-S5. PMID: 26696680 www.ncbi.nlm.nih.gov/pubmed/26696680.

  • Rice JB, Desai U, Cummings AK, Birnbaum HG, Skornicki M, Parsons NB. Burden of diabetic foot ulcers for Medicare and private insurers. Diabetes Care. 2014. 37 (3):651-8.

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