Diabetic Foot
Foot complications of diabetes from nerve damage and poor circulation
Quick Facts
- Type: Complication of diabetes
- Main causes: Nerve damage, reduced blood flow
- Common problem: Slow-healing foot ulcers
- Seek urgent care: Spreading redness, fever, black tissue
Overview
Diabetic foot refers to the collection of foot problems that can develop in people who have diabetes. Persistently high blood sugar over time damages the nerves (neuropathy) and narrows the blood vessels that supply the feet. Together these changes mean a minor cut, blister, or pressure point can go unnoticed, heal slowly, and develop into a serious wound or infection.
The most feared complication is a foot ulcer that becomes infected and spreads to deeper tissue or bone. With careful daily foot care, good blood sugar control, and prompt treatment of any wound, most of these problems can be prevented or caught early. Diabetic foot is one of the most common reasons people with diabetes are admitted to hospital, which is why prevention matters so much.
Symptoms
Because nerve damage can dull pain, the warning signs are not always obvious. Watch for:
- Numbness, tingling, or burning in the feet (a sign of nerve damage)
- Loss of feeling, so cuts or blisters are not felt
- Cool, pale, or bluish skin, or weak pulses in the feet (poor circulation)
- Slow-healing sores, blisters, or cracks, especially on the sole or toes
- Redness, warmth, swelling, or drainage that may signal infection
- Changes in foot shape, calluses, or corns
Any open sore that does not begin to heal within a few days, or that becomes red, warm, or starts to drain, should be checked promptly.
Causes
Two long-term effects of diabetes work together to create foot problems:
- Peripheral neuropathy: High blood sugar damages nerves, reducing the ability to feel pain, heat, or pressure. A small injury can go unnoticed until it becomes serious.
- Poor circulation (peripheral artery disease): Narrowed blood vessels limit the blood flow that wounds need to heal and that the immune system needs to fight infection.
Added pressure from poorly fitting shoes, calluses, or foot deformities concentrates force on certain spots, and the dulled sensation means the person does not shift away from the pressure. Even a small wound can then break down into an ulcer.
Risk Factors
- Long-standing or poorly controlled diabetes
- Nerve damage with loss of sensation in the feet
- Poor circulation or peripheral artery disease
- A previous foot ulcer or amputation
- Foot deformities, calluses, or corns
- Smoking, which further narrows blood vessels
- Vision problems or limited mobility that make foot checks difficult
Diagnosis
A health professional examines the feet and assesses both nerve and blood supply:
- Sensation testing: A thin nylon filament (monofilament) and tuning fork check whether protective sensation is intact.
- Circulation checks: Feeling for foot pulses and measuring blood pressure at the ankle compared with the arm.
- Wound assessment: Measuring the size and depth of any ulcer and checking whether it reaches bone.
- Imaging and lab tests: X-rays or scans and blood tests if infection or bone involvement is suspected.
Treatment
Treatment depends on the problem and aims to heal wounds and prevent amputation.
- Wound care: Cleaning, removing dead tissue (debridement), and dressing ulcers regularly.
- Taking pressure off (offloading): Special shoes, casts, or boots to relieve pressure on an ulcer so it can heal.
- Infection control: Antibiotics for infected wounds; deep or bone infections may need hospital care.
- Improving blood flow: Procedures to open narrowed arteries when circulation is severely reduced.
- Blood sugar control: Keeping glucose in a healthy range supports healing throughout treatment.
A team that may include a podiatrist, vascular specialist, and diabetes doctor often provides the best results.
Prevention
- Check your feet every day for cuts, blisters, redness, or swelling
- Wash and dry feet carefully, especially between the toes
- Wear well-fitting shoes and clean socks; never go barefoot
- Trim toenails straight across and have calluses treated professionally
- Keep blood sugar, blood pressure, and cholesterol in target range
- Stop smoking to protect circulation
- Have your feet examined regularly by a health professional
When to See a Doctor
Contact a health professional promptly for any foot wound that does not start healing, or for new numbness or tingling. Seek urgent or emergency care if you notice:
- Spreading redness, warmth, swelling, or pus around a wound
- Fever or feeling generally unwell with a foot sore
- A wound that suddenly turns black or the skin appears to be dying
- Severe foot pain, or a foot that becomes cold, pale, or numb
These can signal serious infection or loss of blood supply that needs immediate treatment.
Frequently Asked Questions
Why are foot problems so common in diabetes?
Diabetes can damage the nerves and narrow the blood vessels in the feet. This means injuries are not always felt and heal slowly, so small cuts can turn into serious ulcers and infections.
How can I prevent diabetic foot ulcers?
Check your feet every day, wear properly fitting shoes, keep your feet clean and dry, never go barefoot, and keep your blood sugar well controlled. Have your feet examined regularly by a health professional.
Are diabetic foot ulcers an emergency?
An ulcer that is spreading redness, draining pus, turning black, or causing fever needs urgent medical care. Early treatment greatly lowers the risk of deep infection and amputation.
Can diabetic foot ulcers heal?
Yes. Many ulcers heal with proper wound care, pressure relief, good blood sugar control, and treatment of any infection or poor circulation. Healing is faster the earlier care begins.
Does smoking affect my feet if I have diabetes?
Yes. Smoking narrows blood vessels and further reduces blood flow to the feet, making ulcers more likely and slower to heal. Stopping smoking is one of the most helpful steps you can take.
References
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetes and Foot Problems.
- Centers for Disease Control and Prevention (CDC). Diabetes and Your Feet.
- Mayo Clinic. Diabetes and foot care.
- MedlinePlus, U.S. National Library of Medicine. Diabetic foot.