Why a diabetic foot wound needs close watching

Knowing the diabetic foot ulcer warning signs helps you report a problem while it is still small. Diabetes can damage the nerves in the feet, so a sore may hurt far less than you would expect, or not at all. It can also reduce blood flow to the feet and make it harder for the body to fight infection.

That makes pain a poor guide. A foot wound that does not hurt is not necessarily minor. Your eyes, your hands and a daily routine have to do the work that pain would normally do.

Early signs before the skin opens

Many foot ulcers begin as a pressure spot. Tell the clinician who manages your diabetes or foot care if you notice:

  • A thick callus, especially one with a dark or red spot beneath it
  • A blister, or a red mark from a shoe that does not fade
  • A spot that feels warmer than the same place on the other foot
  • Cracked skin on the heel, or soft, broken skin between the toes
  • New swelling, redness or a change in the shape of one foot
  • A stain on your sock or the lining of your shoe

Our guide to daily foot checks for people with diabetes describes a routine for catching these early.

Warning signs in a wound you already have

Contact the treating clinician promptly if you see any of these:

  • Redness, warmth or swelling around the wound, especially if it is spreading
  • More drainage than before, or drainage that turns thick or cloudy
  • A new or stronger smell
  • A wound that is getting larger or deeper, or a new opening nearby
  • Skin at the edges turning dark, purple, gray or black
  • New pain or tenderness in a foot that usually has little feeling
  • Blood sugar readings running higher than usual for no clear reason
  • No sign of improvement when your clinician expected some

On darker skin, redness can be hard to see. Check for an area that looks darker than the skin around it, or that feels warm, firm or puffy. Our guide to the signs of wound infection describes these changes in more detail.

Signs that need urgent or emergency care

Call the treating clinician right away, and go to an emergency department if you cannot reach them, when a foot wound comes with:

  • Fever, chills or feeling generally unwell
  • Redness moving up the foot or leg, or red streaks
  • Sudden severe pain in the foot or leg
  • A black area on a toe, the heel or the wound edge

Call 911 for a foot or toes that suddenly turn cold, pale or blue, or for trouble breathing, chest pain, confusion, fainting or bleeding that will not stop with firm pressure. Gateway is not an emergency service.

What to tell the clinician

Have these details ready when you call:

  1. Which foot, and where on the foot
  2. What you noticed, when you first saw it and whether it is getting worse
  3. Your recent blood sugar readings and any fever
  4. The shoes or protective device you have been wearing, and how much you have been on your feet
  5. Which foot care, diabetes and vascular clinicians are already involved

If you were given a boot, cast or special shoe to keep pressure off the wound, say honestly how often you wear it. Our guide to what offloading is explains why it matters.

What not to do on your own

Your own clinician’s instructions come first. In general, people with diabetes are advised as follows:

  • Do not walk barefoot, even indoors.
  • Do not cut or shave calluses, or use corn and callus removers, unless your clinician has told you to.
  • Do not use a heating pad or hot water on feet with reduced feeling.
  • Do not go back to regular shoes before the clinician says the foot is ready. See choosing shoes with a diabetic foot wound.

How Gateway can help

Gateway arranges wound visits with partner clinicians for people with diabetic foot ulcers at home and in facilities across Greater St. Louis and the Metro East. We also help with diabetic foot care coordination among the podiatry, vascular and primary care offices involved. The treating clinician makes every clinical decision.

You or a family member can call 314-325-0126 or request care, with or without a referral. Availability is confirmed by location and care setting.

Common questions

My foot ulcer does not hurt. Does that mean it is healing?

Not necessarily. Nerve damage from diabetes can dull or remove pain, so a wound can deepen or become infected without hurting. Go by what you can see, smell and measure: size, drainage, color, odor and the skin around the wound.

Is a black or dark area on my toe an emergency?

Treat it as urgent. Dark or black skin can mean the tissue is not getting enough blood, and it needs prompt medical assessment. Call the treating clinician the day you notice it. If the foot is also cold, very painful or pale, or you have a fever, go to an emergency department.

Can a small blister on my foot wait until my next appointment?

With diabetes, report it instead of waiting. A blister shows that something is rubbing or pressing, and it can open into a wound. Leave it intact, keep pressure off the area if you can and call the clinician who manages your foot care. Keep the shoes you were wearing when it appeared so the cause can be checked.

What should a caregiver look for if the person cannot check their own feet?

Look at the tops, soles and heels of both feet and between every toe, in good light, at the same time each day. Compare one foot with the other for color, warmth and swelling. Check socks and shoe linings for stains. Write down anything new with the date, and report it to the treating clinician without waiting for the next visit.

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