Prof. Dr. Aytaç Çetinkaya Diabetic Foot Istanbul

Swollen, Red Foot With Fever

Swelling, warmth and redness in the foot of a person with diabetes can be infection, a clot or Charcot foot. When is it urgent, and what to do?

Medically reviewed: · Prof. Dr. Aytaç Çetinkaya

Short answer

In a person with diabetes, swelling, warmth and redness in one foot is most often due to infection; a clot or Charcot foot can look the same. If it comes with fever, chills or redness spreading up the leg, go to an emergency department. Even without fever, see a doctor within a few days and keep weight off the foot until then.

Hands holding the feet in bed

If there is swelling, warmth and redness in the foot together with fever or chills, the cause may be a skin and soft tissue infection (cellulitis), a deep infection or another problem. In people with diabetes these signs can progress quickly, so it is important to find the cause early instead of waiting.

Emergency: If there is fever, chills, redness spreading up the leg, confusion, a fast pulse or very high blood sugar, go to an emergency department without waiting.

Possible causes

Cause Typical features
Skin and soft tissue infection Redness, warmth, tenderness; usually starts from a wound, a crack or a fungal infection between the toes
Deep infection, abscess Marked swelling, sometimes discharge; there may be little pain; blood sugar rises
Bone infection A wound that has not closed for a long time; a swollen, red toe
Deep vein thrombosis (clot) Swelling and tightness in the calf; there may be no wound
Charcot foot A warm, swollen foot without a wound; in a person with nerve damage; little or no pain
Swelling from fluid (oedema) due to the heart, the kidneys or medicines Usually in both feet; no redness or warmth

The treatments for these conditions are completely different from one another. For example, antibiotics have no place in Charcot foot, where the main treatment is protecting the foot from load; in infection, antibiotics are needed without delay. This is why a doctor needs to tell them apart.

Three things you can check yourself

  1. Compare both feet: Is the swelling on one side only? Is one foot clearly warmer than the other?
  2. Look at the sole and between the toes: Is there a wound, a crack, a blister or a callus? If you cannot see, use a mirror or ask a relative.
  3. Mark the edge of the redness with a pen: If it moves beyond the line within a few hours, the infection is progressing; do not wait.

Until you see a doctor

  • Keep weight off the foot, and keep it raised when sitting and lying down.
  • Do not apply heat or cold.
  • Do not start antibiotics or medicines for swelling on your own.
  • Measure and note your temperature and your blood sugar.
  • If there is a wound, cover it with a clean, dry dressing.

What is done during the assessment?

  1. Examination: The width of the redness, the difference in temperature, whether there is a wound, and the pulses are assessed.
  2. Blood tests: Markers of infection, blood sugar, kidney function.
  3. Imaging: X-ray; Doppler ultrasound if a clot is suspected; MRI to tell deep infection and Charcot foot apart.
  4. Culture: If there is a wound or discharge, a suitable sample is taken.
Examination of the foot with gloved hands

Treatment depends on the cause

  • Infection: Antibiotics by mouth or into a vein, depending on severity; draining of an abscess if there is one. For details, see the diabetic foot infection page.
  • Clot: Blood-thinning treatment, arranged by the relevant specialty.
  • Charcot foot: Protecting the foot from load with a cast or a special boot; followed together with orthopaedics.
  • General swelling from fluid: Managing the underlying heart, kidney or medicine-related cause.

Assessment in Istanbul

With a swollen, red foot, the first question is whether or not the cause is infection. As a specialist in Infectious Diseases and Clinical Microbiology, Prof. Dr. Aytaç Çetinkaya makes this distinction and, if needed, recommends working together with orthopaedics or vascular surgery. If there are no emergency signs, patients in Türkiye and international patients can send comparative photos of both feet and their reports on WhatsApp to ask for a preliminary review. A preliminary review does not replace an examination. If there are emergency signs, do not wait for a reply to your message.

Frequently asked questions

Why does swelling in one foot matter?
Swelling in both feet at once is usually due to the heart, the kidneys or medicines. One-sided swelling, on the other hand, can point to a problem specific to that foot, such as infection, a clot or Charcot foot, and should be assessed.
I have no fever. Could it still be an infection?
Yes. In people with diabetes, a considerable share of serious foot infections occur without fever. The absence of fever is not reassuring; local signs and blood sugar are also taken into account.
There is no wound, but my foot is warm and swollen. What could it be?
In a person with diabetes and nerve damage, a warm, swollen foot without a wound can be the early stage of Charcot foot. In that case, continuing to walk can lead to permanent deformity of the bones; see a doctor and keep weight off the foot.
Should I apply cold or heat?
Do not apply either. On a foot that has lost feeling, heat can cause burns and ice can cause tissue damage. Keeping the foot raised and resting it is enough.

Related pages

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.

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