Diabetes and Your Legs
Why a Sore That Will Not Heal Is a Circulation Warning
A small sore on the ball of your foot. You are not sure when it started. It does not hurt, so you have not thought much about it. Three weeks later it is still there.
For most people a sore like that heals in a few days without any attention at all. When it does not heal in someone with diabetes, there is usually a reason, and the reason is often circulation.
Diabetes puts two problems in the same leg
Diabetes damages nerves and it damages arteries. Both happen slowly, neither hurts while it develops, and together they create a blind spot.
The nerves go first
Nerve damage in the feet, called neuropathy, dulls sensation. A blister, a stone in the shoe, a cut from trimming a toenail. Any of these can happen without you feeling it.
The arteries narrow quietly
Plaque builds up in the arteries feeding the leg and narrows the channel. That is peripheral artery disease, or PAD. Less blood reaches the foot, so an injury that would normally heal in days takes weeks, or never heals.
Put those two together and you get the situation that brings people to us too late. An injury nobody felt, on a foot that cannot heal it.
Why the usual warning sign often does not appear
In most people, PAD announces itself with leg pain when walking that eases with rest. That is a useful warning, and it sends people to a doctor.
In diabetes it is much less reliable. The nerves that would carry the pain signal are often already damaged, so the leg can be badly short of blood and still feel like nothing much. Up to 4 in 10 people with PAD have no leg pain at all, and in diabetes that share is higher.
So the absence of pain is not reassurance here. It is often just the nerves failing to report.
Is It Urgent?
Get seen urgently if:
- A foot wound is spreading, smells, or the skin around it is red and hot
- You have foot pain at rest, especially at night, that eases when you hang the leg out of bed
- Skin on a toe or the foot turns dark
- A foot suddenly becomes cold, pale or numb
These are not wait-and-see symptoms. A foot wound with poor blood supply behind it can move from a small problem to a serious one in days, and most amputations in diabetes begin as a wound that was treatable when it started.
What to look for instead
If pain is unreliable, the feet themselves become the warning system. Worth a proper look:
Any cut, blister, sore or ulcer that has not healed within two weeks
Skin on the foot or lower leg that looks shiny, pale, or bluish
One foot noticeably colder than the other
Hair loss on the toes or lower leg, or toenails that have become thick and slow growing
Numbness, tingling or burning in the feet
Cramping or heaviness in the calf when you walk, even mild
Check your feet, weekly
It takes a minute. Look at the top and sole of each foot, between every toe, and at the heel. Use a mirror on the floor if bending is difficult, or ask somebody. You are looking for anything new: a break in the skin, a colour change, swelling, or a spot that looks different from last week.
Find something, and it is a phone call, not a wait for the next appointment.
Why this matters beyond your feet
Narrowed arteries in the legs are rarely narrowed only in the legs. The same process affects the arteries feeding the heart and brain. In someone with diabetes, finding PAD is one of the clearest signals we get that the whole arterial system needs attention, and it usually arrives while there is still a lot that can be done.
How we test for it
The main test is the ankle brachial index, or ABI. We measure blood pressure in both arms and both ankles and compare them. It takes about 15 minutes, uses nothing more than blood pressure cuffs and a small ultrasound probe, and is low risk.
One thing that matters in diabetes. Long-standing diabetes can stiffen the walls of the ankle arteries, which makes the cuff reading come back falsely high. So a normal ABI does not always rule PAD out. Where that is a possibility we measure the pressure at the toe instead, or look at the shape of the blood flow waveform. Both stay reliable when the ankle reading is not, and a normal ABI taken at face value is one of the more common reasons PAD gets missed in diabetes.
What treatment looks like
Two things run in parallel. Protecting the heart and brain, and getting enough blood to the foot for it to heal.
Protection is medication and risk factor control: a statin, blood pressure treated to goal, glucose controlled, an antiplatelet such as aspirin, and stopping smoking, which does more here than anything else.
Blood flow is where procedures come in. If a wound will not heal or the foot is at risk, we open the narrowed artery, usually through a catheter with a balloon and often a stent, through a small puncture in the groin or wrist. More extensive disease is sometimes better treated with bypass surgery. Wound care alone rarely succeeds if the blood supply behind the wound has not been restored.
FAQs
Common questions
My feet are numb but they do not hurt. Is that worth checking?
Yes, and the numbness is part of the reason. Numb feet cannot warn you about an injury, and they cannot warn you about poor circulation either. It makes checking more important, not less.
My ABI was normal. Does that settle it?
Usually, but not always in diabetes. If the arteries at the ankle are stiff the reading can come back falsely high. If there are symptoms or a wound that will not heal, a toe pressure or a waveform tells us more.
How often should I be checked?
It depends on how long you have had diabetes and what else is going on. As a rule it is worth raising at an annual review once you are over 50, and sooner if you have any of the signs above.
The short version
Diabetes damages nerves and arteries at the same time, so a foot can be short of blood and feel fine. A sore that has not healed in two weeks is the sign to act on, not pain. Checking takes 15 minutes, and it is far easier to protect a foot before a wound appears than to heal one after.
You can read more about peripheral artery disease and its symptoms on our
PAD page.
Book Your Next Appointment
Getting assessed at Lumen Heart and Vascular
At Lumen Heart and Vascular we can work this up properly in one visit, from screening and risk factor treatment through to opening the leg arteries or surgery when PAD is severe. If you have diabetes and any of this sounds like you, an ABI is a quick way to get a clear answer, and it is far better done before a wound appears than after.
We see patients at 13411 Parker Commons Blvd, Fort Myers, and care for people across Lee and Collier counties, including Cape Coral, Estero, Bonita Springs and Naples. We can usually see new patients within 1 to 2 days, pending insurance approval.
Call (239) 415-4900 or use the contact page to book. Physicians referring a patient can find what we need on the referral page.
This page is general education and not a substitute for individual medical advice. If you have symptoms or concerns, contact your physician or seek emergency care.
