Diabetic Foot Infection
What a diabetic foot infection is, how to spot it, which tests are done and how treatment is planned, as seen by an infectious diseases specialist.
Short answer
A diabetic foot infection is when bacteria settle in a wound on the foot of a person with diabetes. It shows itself through redness, warmth, swelling, discharge or a bad smell; there may be no pain. Depending on how severe the infection is, treatment combines antibiotics, wound cleaning and, when needed, surgery. If there is fever or rapidly spreading redness, assessment is needed the same day.
A diabetic foot infection develops when bacteria settle in a wound or a break in the skin on the foot of a person with diabetes. It covers a wide range, from a mild skin infection to conditions that reach the bone and can be life-threatening. In people with diabetes, a considerable share of foot wounds become infected over time, and these infections are one of the main causes of diabetes-related amputations. That is why recognising it early and managing it correctly makes a decisive difference.
Why is it more common and more severe in diabetes?
Three factors work together:
- Nerve damage (neuropathy): Because the sense of pain is reduced, a small wound, a blister from rubbing or a burn goes unnoticed, and the person keeps walking on it.
- Poor circulation: When less blood reaches the foot, neither the body's defence cells nor antibiotics can reach the wound in sufficient amounts.
- High blood sugar: It weakens the function of immune cells and slows wound healing.
Which signs suggest infection?
- Redness, warmth or swelling in or around the wound
- Pus, discharge, a bad smell
- Increasing pain or tenderness around the wound
- The wound getting larger or deeper, or hardness around it
- Fever, chills, weakness
- An unexplained rise in blood sugar
In diabetes the signs can remain subtle. The absence of pain does not mean the absence of infection. Sometimes the only clue is blood sugar that has gone out of control.
How is the severity of infection classified?
The treatment decision is based on the severity of the infection. International guidelines (IWGDF/IDSA) define three levels:
| Level | Findings | General approach |
|---|---|---|
| Mild | Skin and the tissue just beneath it only; redness limited to the area around the wound | Usually outpatient treatment and close follow-up |
| Moderate | More extensive redness, or involvement of deep structures (tendon, joint, bone) | Outpatient or inpatient treatment; a surgical opinion may be needed |
| Severe | Signs that affect the whole body, such as fever and a fast pulse | Hospital admission, antibiotics into a vein, urgent surgical assessment |
What is done during the assessment?
- Examination: The size and depth of the wound are measured. A sterile instrument is used to check whether the wound reaches the bone.
- Blood tests: Markers of infection (CRP, sedimentation rate, white blood cell count), blood sugar and kidney function.
- Culture: After the wound has been cleaned, a sample is taken from deep tissue. A surface swab can be misleading.
- Imaging: X-ray first. If bone infection or a deep abscess is suspected, an MRI may be requested.
- Circulation: Blood flow to the foot is assessed through the pulses and, if needed, Doppler.
How is treatment planned?
Treatment does not consist of a single medicine; several parts run together.
Antibiotics. The choice depends on the severity of the infection, the likely bacteria, previous antibiotic use, kidney function and the culture result. In mild infections, treatment by mouth is often enough. In severe cases it is started into a vein and continued by mouth once improvement is seen. According to current guidelines, the duration for soft tissue infections is usually 1 to 2 weeks; it can be extended in extensive or slowly improving cases. Treatment that is longer than necessary brings no benefit and increases the risk of resistance and side effects.
Wound cleaning and surgery. Antibiotics alone are not enough unless dead and infected tissue is removed. If there is an abscess, it is drained. In deep infections the decision is made together with the surgical team.
Restoring circulation. If blood flow is inadequate, an assessment by vascular surgery or interventional radiology is requested.
Offloading and wound care. Keeping weight off the wound and using a suitable dressing are basic conditions for healing.
Blood sugar control. Infection raises blood sugar, and high blood sugar feeds the infection; this cycle needs to be broken.
When is it an emergency?
What can you do?
- Do not start antibiotics on your own, and do not use old medicines you have at home.
- Do not squeeze or cut the wound, and do not apply herbal mixtures to it.
- Cover it with a clean, dry dressing and keep weight off the foot.
- Bring the medicines you take and any earlier culture and test results with you.
- Take a photo of the wound; it helps to follow the course.
Assessment in Istanbul
Prof. Dr. Aytaç Çetinkaya is a specialist in Infectious Diseases and Clinical Microbiology; diabetic foot infections are his main field of work. In Istanbul he assesses patients who come from other cities in Türkiye and from abroad. International patients can send a photo of the wound, their reports and a short note on WhatsApp to ask for a preliminary review. A preliminary review does not replace an examination.
Frequently asked questions
Is every diabetic foot wound infected?
Are antibiotics alone enough?
How long does antibiotic treatment last?
Is a swab culture from the wound enough?
When is a hospital stay needed?
References
This page is for general information only and does not replace an examination, diagnosis or treatment. In an emergency, call your local emergency number or go to the nearest emergency department.