Understanding the Relationship Between Diabetes and Foot Infections

Having diabetes puts you at risk of foot infection. A diabetic foot infection results from bacteria entering the skin through a wound, ulcer, or break in the protective barrier of the foot.

Diabetic foot infection often results from a combination of nerve peripheral neuropathy, poor blood flow and impaired immune response caused by high blood sugar levels. These interconnected conditions compromise the body’s natural ability to defend against infections and heal.

Peripheral neuropathy: One of the complications of diabetes is neuropathy, which is damage or dysfunction to one or more nerves. Neuropathy can result in tingling, muscle weakness and pain in your feet. CDC estimates that about half of all people with diabetes have some kind of nerve damage. Most damage is to nerves in feet and legs.[1]  Neuropathy can cause numbness so that you might not feel a foot injury, cut or even a blister that could result in an ulcer.

Poor circulation: Peripheral Artery Disease (PAD) is a complication of diabetes. It reduces blood flow to the feet and delays wound healing, which can increase the risk of diabetic foot infection.

Impaired immune response: High blood can trigger inflammation - your body’s protective immune response – which makes your immune system work harder. When your immune system is weakened due to inflammation, it is harder for your body to fight off infections, including skin infections. Even a small, treatable wound or injury like a cut, blister or callus can turn into a severe infection. Diabetes makes it more difficult for such injuries to heal, which makes it easier for bacteria to grow and cause infections. 

Recognize a diabetic foot infection

The earliest warning signs of a diabetic foot infection are:

·         Swelling, warmth or redness around the wound or ulcer

·         Skin discoloration or darkening

·         Drainage or pus coming from any skin opening

·         Foul-smelling odor coming from the foot

·         A tender spot on your foot

·         Visible bone or deep tissue through an ulcer

In addition to visible signs of a diabetic food infection, there are systemic symptoms including: [2]

• Fever or chills indicating systemic infection
• Elevated blood sugar levels that are difficult to control
• Fatigue or general feeling of illness
• Loss of appetite

Foot ulcers and diabetes foot infections

Foot ulcers are a considerable problem for people with diabetes. They can become infected, often leading to hospitalization. Once peripheral neuropathy develops, the annual incidence of ulcer formation increases from less than one percent to greater than 7%.[3] Diabetes-related foot infections develop in approximately 40% of diabetes-related foot ulcers.[4]

Left untreated due to diminished sensation, a diabetic foot ulcer can get worse over weeks or months without someone knowing because they do not feel the pain. In the initial stages, a diabetic foot ulcer can be treated successfully, increasing the chance of a full recovery. However, in advanced stages, the risk of complications like a foot or limb amputation are high. 

Know the stages of a diabetic foot ulcer

Doctors use classification and a scoring system to determine the severity of a diabetic foot ulcer and proper treatment. There are several classification systems, but the Wagner Ulcer Classification System is used most often. It uses six grades (0 to 5) that focus on the depth of the ulcer penetration, the extent of the tissue necrosis, and the presence of infection and inflammation of the bone or osteomyelitis (OM).

Grades are:[5]

Grade 0: intact skin

Grade 1: Superficial ulcer

Grade 2: Deep ulcer

Grade 3: Ulcer with bone involvement

Grade 4: Forefoot gangrene

Grade 5: Full-foot gangrene

Treatment for diabetes related foot infections

Diabetic foot infection treatment varies and depends on the severity of the infection. Oral antibiotics may be used for mild and some moderate infections. In the case of severe infections, treatment for diabetes related foot infections requires intravenous antibiotics, typically taking one to two weeks or longer for infections that are slow to resolve or for or osteomyelitis. For infections that are severe or persistent, treatment may involve surgery and specialized team-based wound care. [6]

Prevent diabetic foot infections

To reduce the risk of developing foot problems that can occur when you are living with diabetes:

·         Check your feet every day for sores, cuts, blisters, corns, or redness.

·         Trim nails carefully. Be sure to trim toenails straight across—cutting into the corners of nail can cause ingrown toenails. File down sharp edges with an emery board.

·         Wash your feet daily with warm soapy water. Dry feet thoroughly.

·         Moisturize your feet but avoid applying lotion between the toes, which can lead to infections.

·         Avoid going barefoot, even in the house. Wear socks and shoes. Moisture wicking diabetic socks offer extra protection. Diabetic shoes are designed to prevent pressure on feet to prevent blisters and hot spots that can lead to infection.

·         Exercise to stimulate circulation in the feet and legs.

·         Follow directions from your diabetes care team about managing glucose and keeping blood pressure and cholesterol levels under control. Contact your care team if you experience numbness or cuts and ulcers that are not healing.

Bottom line: stay on your toes to prevent diabetic foot infections.