You take off a new pair of shoes and spot a small bubble on your heel. It barely hurts, but you have diabetes, and you are unsure whether it can wait. A foot blister with diabetes deserves a call to your health care team as soon as you find it, even if the skin still looks intact. Protect the area from more rubbing while you arrange advice. If redness is spreading, the foot is getting hotter or more swollen, or you feel unwell, seek urgent medical care.
What to do when you first see the blister
Sit down and take off the shoe and sock so you can see the entire area. Use a mirror for the sole or heel, or ask someone you trust to look. Check the same area on the other foot for comparison. Pay attention to changes in colour, warmth and swelling as well as the blister itself. A brief look in good light is more helpful than pressing on the spot to see whether it hurts.
Protect the skin and stop the rubbing
Leave an intact blister closed. Its thin roof helps protect the skin underneath. Avoid piercing it, trimming it with scissors or peeling away loose skin. If it opens, gently clean the area with mild soap and lukewarm water, pat it dry and cover it with a clean, non-stick dressing. Ask the health care professional you call what to use if your skin reacts to adhesive or you already have a wound care plan.
Put aside the shoe that rubbed. While waiting for guidance, reduce unnecessary walking and avoid going barefoot. If you need to get around, choose footwear that protects the foot without pressing against the dressing. Use your usual mobility aid if you have one. If you cannot move safely without putting pressure on the area, tell the clinician when you call so they can advise on what to do next.
Make the call even if you feel fine
Say that you have diabetes and have found a new blister on your foot. Give the location, when you first saw it, and whether it is open or draining. Mention any history of foot ulcers, reduced feeling, circulation problems or previous foot surgery. If your regular provider cannot advise you promptly, contact another health care service for timely guidance. The Diabetes Canada foot care checklist explains which changes deserve immediate attention.
Why the amount of pain can be misleading
Diabetes can affect the nerves that carry sensation from the feet. When that happens, a seam can rub for hours without the usual sting that would tell you to change shoes. Someone with reduced feeling might notice a blood spot on a sock before noticing a sore. Even people who can feel pressure or temperature in part of the foot may have patches where sensation is less reliable.
Blood flow matters for a different reason. Reduced circulation can make it harder for damaged skin to heal. Nerve changes and circulation problems can occur together, but either one can change what a clinician recommends. At an assessment, the team may examine the surrounding skin, check sensation or circulation and look at the footwear or insert that may have caused the friction. What they find guides how soon the area needs reassessment and whether pressure relief is needed.
When a blister needs urgent attention
Check for a widening area of redness, a marked change in warmth, increasing swelling, fluid that looks like pus, or a new bad smell. On darker skin, a change may appear as a darker or purplish patch rather than bright redness. Seek urgent assessment if you notice these signs, or if you have new blackened skin. If redness is spreading rapidly, or you have fever, chills or feel very unwell, go to an emergency department. A photograph or online message should never delay urgent assessment.
What to tell the clinician if the change is hard to describe
Describe the change in plain language. You might say the skin is warmer than the other heel, the damp spot on the dressing is larger than it was this morning, or the toes suddenly look different. Mention when you last walked on the foot and whether there was an injury, new shoe or change of activity. If your clinician asks for a photograph, include enough of the foot to show where the blister is and follow their instructions for sending it securely.
Why a hot, swollen foot needs a closer look
Warmth and swelling can have several causes. A blister may be visible while the more important problem lies deeper in the foot. Tell the clinician if the entire foot is hot or swollen, if its shape looks different or if your shoe suddenly feels much tighter on that side. Those details help them decide how urgently you need examination, particularly when reduced sensation makes it hard to judge the severity of a problem.
Trace the rubbing before returning to the same shoes
Once a clinician has advised you on the immediate problem, think back to what was different that day. A heel blister might follow a loose shoe sliding with each step. A sore on top of a toe can come from a low toe box or a thick sock that takes up space. The edge of a new insert, a folded liner or a small object inside the shoe can leave a mark in a very specific spot.
Look inside both shoes in good light. Compare the seams and check whether the liner is flat. Bring the shoes, socks and any removable inserts to a follow-up visit if the clinician asks. A professional can compare the position of the sore with the shoe and review how to measure your feet for a better fit. Even shoes you have worn for years can begin rubbing as their lining wears or the shape or size of your feet changes.
Keep a short note of when a problem occurred and what you wore. For example, a blister that follows an afternoon of errands in a stiff boot gives different clues from one that appears after a long day in slippers. If a dressing makes an otherwise comfortable shoe feel tight, ask about safe options before using it again. The aim is to keep pressure away from the healing spot while preserving enough stability for safe movement.
Plan the next check before you leave the appointment
Ask who will check the area next, how soon to return and what change would move that date forward. If you have difficulty seeing the sole or reaching the dressing, tell the clinician while they are making the plan. A mirror, a trusted person or another care arrangement may make a daily check practical. The clinic’s guide to routine foot care for people with diabetes can help you fit those checks into a regular habit once the immediate concern is addressed.
After the skin has healed and your care team says it is safe to resume your usual activity, inspect the area again when you change shoes or increase walking. A red mark, rubbed patch or damp spot on a sock is a reason to stop and look before the next outing. If blisters keep forming in the same place, mention the pattern. Repeated rubbing can be easier to investigate when you bring the exact footwear and describe when the changes appear.
For follow-up after a blister has been assessed, speak with the Steady Foot Clinic team in North York about diabetic foot care and a footwear review.