What a diabetic foot ulcer is

These diabetic foot ulcer basics are written for someone hearing the term for the first time. A diabetic foot ulcer is an open sore on the foot of a person with diabetes. Most form on the bottom of the foot, under the ball of the foot or the big toe, on the tips of the toes or on the heel.

It may look like a small crater ringed by thick callus, and it may not hurt at all. It is taken seriously because an open wound on the foot can become infected, and a deep infection can threaten the foot. The approach to care is well established, and it works better the earlier it starts.

Why diabetes leads to foot ulcers

Usually several things combine.

  • Nerve damage. Years of high blood sugar can dull feeling in the feet. A blister, a pebble or a tight shoe goes unnoticed, and you keep walking on it.
  • Reduced blood flow. Diabetes raises the chance of narrowed arteries in the legs. Less blood reaching the foot means slower repair and a weaker defense against germs.
  • Changes in foot shape and skin. Toes can curl, skin dries and cracks, and callus builds up over the spots that carry the most weight.
  • High blood sugar itself. It slows healing and makes infection harder to fight.

What the clinician checks first

At early visits the treating clinician will usually:

  • Measure the ulcer and check how deep it goes
  • Look for redness, warmth, swelling, drainage and odor
  • Check blood flow by feeling pulses, and sometimes order pressure tests at the ankle or toe
  • Test how much feeling you have in both feet
  • Look at your shoes and how you walk
  • Decide whether an X-ray or lab work is needed

Bring the shoes you wear most, your glucose log or meter, and your medication list.

The main parts of treatment

A plan for a diabetic foot ulcer usually has several parts working together. The treating clinician decides which apply to you.

  1. Taking pressure off the wound. This may involve a cast, boot or special shoe. The guide to what offloading is explains it.
  2. Removing callus and dead tissue. A clinician does this so healthy tissue can grow.
  3. Choosing a dressing. The dressing keeps the wound covered and at the right moisture level.
  4. Finding and treating infection. The clinician decides whether tests or medication are needed.
  5. Checking blood supply. If flow is poor, a vascular specialist may be asked to evaluate.
  6. Managing blood sugar. Your primary care or diabetes clinician leads this. The guide to wound care and blood sugar explains the connection.

Your part between visits

  • Keep weight off the ulcer exactly as directed, for every step.
  • Keep the dressing clean and dry, and change it only as you were shown.
  • Wear protective footwear indoors too. Do not walk barefoot.
  • Look at both feet every day, including the soles and between the toes. The guide to daily foot checks for people with diabetes shows a simple routine.
  • Leave callus, corns and thick nails to a clinician. Do not cut them or use medicated pads.
  • Avoid soaking the foot, heating pads and hot water unless the clinician tells you otherwise.
  • Follow the blood sugar plan your diabetes clinician gave you, and write down your readings.

Warning signs to report

Call the treating clinician right away if you notice:

  • Redness, warmth or swelling that is spreading
  • Cloudy or thick drainage, or a new odor
  • New pain in a foot that is usually numb
  • A wound that looks larger or deeper, or skin turning dark
  • Red streaks moving up the foot or leg
  • Fever, chills, or blood sugar running higher than usual without a clear reason

Call 911 for confusion, fainting, trouble breathing, shaking chills with a high fever, or a foot that suddenly turns cold and pale. The guide to diabetic foot ulcer warning signs goes into more detail.

Your care team and how Gateway helps

A foot ulcer often involves a primary care clinician, a podiatrist, a wound care clinician and sometimes a vascular specialist or home health nurse. Gateway arranges visits with partner clinicians across Greater St. Louis and the Metro East and coordinates records, orders, supplies and updates among those offices. Read about diabetic foot ulcer care, diabetic foot care coordination and diabetes care in primary care. To get started, call 314-325-0126 or send a request for care.

Common questions

Is a diabetic foot ulcer the same as a callus or a blister?

No, though it often starts as one. A callus is thickened skin over a pressure point. An ulcer is an open wound that goes through the skin. Sometimes an ulcer is hidden beneath callus and is found only when a clinician trims it. Show a clinician any callus with a dark spot, drainage or a soft center.

Does a foot ulcer mean my diabetes is out of control?

Not necessarily. Nerve and circulation changes build up over many years, so an ulcer can appear even when recent numbers have been good. Sharing your readings with your diabetes clinician helps, because blood sugar affects healing from this point on.

Does having a foot ulcer mean I will lose my foot?

An ulcer by itself does not mean amputation. That becomes a concern when a wound is deeply infected or the foot is not getting enough blood, and the purpose of early, consistent care is to head off both. Ask the clinician directly about your circulation and any sign of infection. The page on limb preservation describes how the specialists involved work together.

What should I write down between visits?

Keep a short daily note. Record your blood sugar readings, whether you wore your offloading device all day, what the dressing looked like when it came off, and anything new: drainage on your sock, a smell, swelling, a fall. A dated list gives the clinician a clearer picture than memory does.

Related pages

General information to help you talk with your own clinician. It is not medical advice, and the treating clinician makes every clinical decision. For a medical emergency, call 911.

Updated October 2026