An arterial ulcer is a wound that stays open because too little blood is reaching it. The skin has not failed. The supply line feeding that skin has narrowed, and tissue living on a thin ration cannot fund a repair.
That single fact reorganizes everything else. Dressings, creams and cleaning routines all sit downstream of a problem none of them touch, which is why these wounds so often sit still for months under perfectly reasonable care. This guide covers what ischemia does to a foot, the six features that point at circulation, how the disease reaches the point of breaking the skin, why an arterial wound can look calm while it is in trouble, and what treatment actually aims at.
On this page
- What is an arterial ulcer?
- The wound is the symptom, not the disease
- Six signs the blood supply is the cause
- How ischemia reaches the point of an ulcer
- Why an arterial wound can look deceptively calm
- How a clinic measures the blood supply
- Restoring flow comes first
- What you can do
- What to avoid
- Living with an arterial ulcer
- When to have it assessed
- Questions people ask
- The takeaway
What is an arterial ulcer?
It is an open sore, usually on the foot or lower leg, caused by inadequate arterial blood flow to that patch of tissue. Clinicians call the underlying state ischemia, meaning a part of the body is receiving less blood than it needs to work properly and to mend itself.
The condition behind almost all of them is peripheral artery disease. Fatty deposits called plaque build up inside the artery walls over years, the channel through the middle narrows, and the volume of blood arriving at the far end of the limb drops. The National Heart, Lung, and Blood Institute’s overview of peripheral artery disease sets out the wider condition and who tends to develop it.
Location follows the plumbing. Blood pressure and flow are lowest at the end of the line, so the toes are affected first, with the heel, the shin and the bony bump on the outside of the ankle close behind. Anywhere a shoe presses is a candidate too, because pressure on top of a poor supply closes the last of it off.
What opens these wounds is usually trivial. A new pair of shoes, a nail cut a fraction too short, a knock against a table leg, a blister from one long day. On a well supplied foot none of those would leave a mark for more than a week. On a foot running near the limit of its blood supply, the same small injury has nothing behind it to close it, and what should have been a scab becomes a wound with a date of onset the person can name exactly.
The wound is the symptom, not the disease
Look at an open sore and the natural conclusion is that the skin needs help. Better cleaning, a stronger dressing, an antibiotic cream, more frequent changes. The reading is understandable and it aims at the wrong organ.
Healing is expensive. Closing a wound means building new blood vessels, laying down collagen, multiplying skin cells at the edges and running an immune response in the middle, and every one of those jobs burns oxygen and fuel that only circulating blood delivers. Repairing skin costs a limb considerably more than simply keeping that skin alive does. So a foot with just enough flow to stay intact can be pushed past its budget by a wound the size of a fingernail, and then it has no way to pay for the repair.
No dressing delivers blood. Until the supply question is answered, wound care can protect an arterial ulcer and keep it clean, but it cannot close it.
There is a second consequence, and it reaches well beyond the foot. Plaque does not build up in one artery in isolation. Someone whose leg arteries have narrowed enough to break the skin very often has the same process underway in the vessels feeding the heart and the brain, which is why this condition is treated as a cardiovascular problem that happens to have announced itself at the ankle. Medication aimed at cholesterol, blood pressure and clotting is part of the plan for that reason, and not because anyone expects a tablet to close the wound.
Sorting an arterial wound from the venous and diabetic patterns, which need almost opposite handling, is worked through in our comparison of leg ulcer types.
Six signs the blood supply is the cause
No single feature settles it, and none of these replaces having the circulation measured. Together they are usually enough to tell you that the artery question needs asking out loud at the next appointment.
The first is where it sits. Toes, the tip or side of a toe, the back of the heel, the bony point on the outside of the ankle, or the shin. Wounds at the inner ankle usually have a different story behind them.
The second is pain that seems far too large for the wound. A shallow sore on a toe that keeps someone awake is a circulation finding, because the pain is coming from starved tissue around the wound and not from the break in the skin.
The third is what position does to that pain. Lying flat takes away the small assist that gravity was giving to a weak supply, so the pain builds through the night and peaks in the early hours. Hanging the foot over the edge of the bed lets gravity push blood downhill again, and the relief that follows within minutes is the clearest sign in the whole list. People work this out years before anyone explains it to them, and end up sleeping upright without knowing why it works.
The fourth is temperature and pulse. One foot cooler than the other, and a pulse at the ankle or across the top of the foot that is faint under the fingers or cannot be found at all.
The fifth is the state of the skin around the wound. Hair thins out over the toes and shin, the skin goes tight and glossy, nails thicken and grow slowly, and the color shifts with position: pale or waxy when the leg is lifted, then flushing a deep dusky red when it is put back down. Tissues that have been rationed for years look rationed.
The sixth is the wound itself, which tends to look strangely inactive. Very little fluid, a base that is pale, gray or covered in dry dark tissue instead of healthy red granulation, and a rim that looks stamped out with a punch. Healthy healing is a busy, wet, red process. An arterial wound rarely manages any of it.
How ischemia reaches the point of an ulcer
Arteries narrow slowly, and the leg compensates for a long time by growing small detour vessels around the blockage. Symptoms appear when the compensation runs out, and they arrive in a recognizable order.
Stage two has a name, claudication, and a very particular character: a cramping ache in the calf or thigh that comes on after a fairly predictable walking distance, then fades within a few minutes of standing still. It is muscle asking for more blood than the narrowed artery can supply during exercise.
The catch is that most people with the disease never get that warning. The National Heart, Lung, and Blood Institute puts the figure at roughly one in four experiencing this classic walking pain, which means the majority reach an assessment either by accident or at the point where skin has already broken down. Anyone who has quietly stopped walking as far as they used to, and put it down to age or a knee, may have skipped the warning without noticing it.
Stages three and four together carry a formal label, chronic limb-threatening ischemia, and the wording is deliberate. At that point the limb has stopped being able to maintain itself at rest, and delay costs tissue. That is the reasoning behind treating a small painful toe wound on a cold foot as more pressing than a large wound on a warm one.
Why an arterial wound can look deceptively calm
Because the signs everyone is taught to watch for are themselves delivered by the bloodstream.
Redness, heat, swelling and pus are what an immune response looks like when it arrives in force. All of it travels in through the arteries. A foot that cannot deliver enough blood to heal also cannot deliver a convincing inflammatory response, so an infection sitting in an ischemic wound may show only a modest pink edge and a little cloudy fluid while doing real damage underneath. Judging that wound by the usual checklist underestimates it.
In a poorly supplied foot, whole-body signs often appear before local ones. Feeling unwell, losing appetite, a rising temperature, or blood glucose that suddenly refuses to behave can all be the first evidence of infection in a wound that still looks unremarkable.
Depth is the other thing that hides. A toe ulcer sitting directly over bone has very little tissue between the two, and infection that reaches bone changes both the antibiotics used and the length of treatment. What raises that suspicion, and the simple check clinicians use at the bedside, appears in our article on wounds that have reached the bone.
The practical rule is to track change instead of appearance. A wound that is bigger, darker, wetter or more painful this week than last is telling you something, whatever the redness is doing.
How a clinic measures the blood supply
The purpose of the assessment is not to choose a dressing. It is to answer one question: can flow to this foot be improved, and how soon does that need to happen.
Hands come first. Pulses are felt at the ankle and on the top of the foot, both legs compared, skin temperature checked with the back of the hand, and capillary refill timed by pressing a toe pad and watching how long the color takes to come back. A handheld Doppler probe then turns flow into sound, and the quality of that sound carries information the pulse alone does not. A healthy artery gives a crisp triple beat. As disease progresses the signal flattens toward a single soft whoosh, and a clinician listening to it learns something before any number is generated.
Then pressures. The ankle-brachial index compares blood pressure at the ankle against blood pressure at the arm, and the resulting ratio is the standard screen for narrowed leg arteries. It has one well known blind spot: long-standing diabetes and kidney disease stiffen the artery walls, the cuff struggles to compress a rigid vessel, and the reading comes back falsely reassuring. Where that is suspected, pressure is measured at the toe instead, since the small vessels there tend to escape the hardening.
Imaging follows when a procedure is on the table. Duplex ultrasound maps where the narrowing sits and how tight it is without any injection, and detailed scanning of the arteries with contrast dye is generally reserved for planning the intervention itself. Sensation is tested at the same visit, because nerve damage and poor flow occur together often enough that assuming one rules out the other is a mistake.
Restoring flow comes first
Everything else is built around whether the blood supply can be improved, so that decision is usually made before the wound plan is finalized.
Two broad routes exist. A narrowed segment can sometimes be opened from the inside using a fine tube threaded through the artery, with a balloon inflated at the blockage and a small metal scaffold left behind in some cases. Where the diseased stretch is long or unsuitable for that, a bypass may be considered, routing blood around the blockage through a length of the patient’s own vein or a synthetic tube. Which approach suits a given person depends on where the disease sits, how long the affected segment is, and their general health, and that judgment belongs to a vascular team.
Medication runs alongside, typically aimed at cholesterol, clotting and blood pressure, with glucose control added where diabetes is in the picture. None of it is wound treatment in any direct sense. It is aimed at the disease that produced the wound and at the heart and brain arteries carrying the same plaque.
Wound care then does the work it can do. Infected or wet dead tissue is removed so infection has less to feed on. Dressings are chosen to protect the wound and manage what little fluid there is. Pressure is kept off the area, which matters as much here as it does with a numb foot, and the devices used for that are set out in our guide to offloading a foot ulcer. Pain relief is part of treatment and not an optional extra, since ischemic pain at night is among the hardest kinds to live with.
One instruction surprises almost everybody. Dry, hard, black tissue on a heel, with no wetness, no smell and no surrounding redness, is often deliberately left alone on a foot with poor circulation. It is acting as a biological cover over tissue that cannot yet support an open wound, and opening it up before flow is improved can convert a stable situation into an unstable one. That call belongs to the clinician assessing the foot, and the reasoning is worth understanding before pressing for it to be cleaned off. Where flow has been restored and a wound still refuses to close, the therapies used at that stage sit within advanced wound care.
What you can do
The single most powerful action available belongs to you and not to any clinic: if you smoke, stopping changes the outlook for the limb more than anything else on this page. Tobacco constricts vessels, accelerates the plaque and worsens the odds of a bypass or stent staying open afterward. Support to quit is worth asking for directly, and asking more than once if the first attempt does not hold.
Take the prescribed tablets as directed even though they do nothing you can see. They are treating the artery, and the artery is treating the wound.
Protect the foot with something on it at all times, indoors included, and check both feet daily using a mirror or a phone camera for the parts you cannot see. Sweep a hand through each shoe before putting it on. Keep the skin supple with a plain moisturizer, avoiding the spaces between the toes where dampness causes its own problems, and leave nails and hard skin to a professional.
Warmth helps, and the safe version is layers: loose socks, blankets, a warmer room. Where night pain is the problem, raising the head end of the whole bed on blocks tilts the body so gravity assists the foot, which works better than piling pillows under the knee and avoids leaving a leg bent for hours.
Walking regularly, stopping when the cramp starts and going again once it settles, encourages those detour vessels to develop and can extend the distance managed over a few months. That advice applies to claudication. Once there is an open wound on the foot, how much walking is appropriate becomes a question for the team treating it, since the same steps that build circulation also load the wound.
What to avoid
Never warm a cold foot with a direct heat source. Hot water bottles, electric blankets, radiators, car heaters and hot soaks all burn skin that has too little blood flow to carry heat away, and a burn on an ischemic foot is a second wound on tissue that could not manage the first one. The instinct to warm a cold foot is exactly right; the method has to be indirect.
Do not put on compression stockings, socks or wraps that were bought without an assessment. Firm pressure applied to a leg with a poor arterial supply squeezes what little is getting through, and that combination causes documented harm. The ankle pressure reading exists to determine whether compression is safe for you specifically.
Keep medicated corn removers, wart treatments, callus files and scissors away from the foot. Those products work by destroying tissue and cannot tell a callus from living skin, and on a foot with borderline circulation a self-treated corn is a common route to an ulcer over the same spot.
Do not soak, soften or peel dry black tissue on a heel or toe, and do not push for it to be removed before circulation has been measured. Stable dry tissue on a poorly supplied foot is doing a job.
Finally, do not abandon the medication or the walking once the wound closes. The narrowing that caused it is still there, and recurrence in the same foot is common among people who understandably treat the healed skin as the end of the story.
Living with an arterial ulcer
The part clinical summaries leave out is that this condition mostly attacks sleep and distance.
Night pain drives people into armchairs, and sitting upright all night does bring relief. It also lets fluid pool in the lower legs, so the ankles swell, the swelling presses on tissue that was already short of blood, and the arrangement that made the night bearable quietly makes the foot worse. Anyone who has moved permanently into a chair should say so at their next appointment, because there are better answers than that compromise, including proper pain relief and getting the flow question in front of a vascular team.
Distance shrinks in a way that is easy to hide. The walk that used to be nothing becomes a route planned around benches, the far end of a parking lot becomes a real obstacle, and social invitations start getting declined for reasons that sound like something else. Cold feet become a constant, socks go on in bed, and summer stops making any difference.
Then there is the fear almost nobody says out loud, which is losing part of the foot. It deserves a plain answer instead of silence. The entire point of the assessment and any procedure that follows is to keep the limb, outcomes have improved considerably as techniques for reopening arteries have developed, and the people most at risk are generally those who arrive late. Ask your team directly where you stand. A specific answer about your own circulation is far more useful, and usually far less frightening, than anything a search engine will offer you at two in the morning.
When to have it assessed
Any break in the skin on a foot or toe that has not closed within two weeks deserves an assessment, and that threshold drops to a few days when several of the six signs are present or when you have diabetes.
Make it sooner if pain wakes you at night and settles when the foot goes down, if a wound on a toe or heel has stayed exactly the same size for weeks, or if nobody has ever felt for the pulses in that foot. A wound being dressed month after month while the circulation behind it has never been measured is the most common way an arterial ulcer becomes a long-term problem.
Seek care the same day for a foot that turns suddenly cold, pale or numb with severe pain, for tissue that is going black or spreading, for redness climbing the leg, or for a raised temperature and feeling generally unwell alongside a foot wound. A limb that changes abruptly is treated as an emergency, since blood flow that has stopped altogether is judged in hours.
Questions people ask
Can an arterial ulcer heal?
Many can, provided the blood supply to the area is improved. Healing depends heavily on whether a narrowed artery can be opened or bypassed, on infection being controlled, and on pressure being kept off the wound. Where flow cannot be improved, the aim shifts toward keeping the wound stable, controlling pain and protecting the foot.
Why does my foot hurt more in bed at night?
Lying flat removes the downhill assist that gravity gives to a weak arterial supply, and the foot then receives even less. Pain that builds after lying down and eases when the foot is lowered toward the floor is a recognized pattern in poor circulation and should be reported specifically, since it changes how urgently circulation is investigated.
Is an arterial ulcer the same as gangrene?
No. An ulcer is an open wound in tissue that is still alive but poorly supplied. Gangrene means tissue that has died, usually appearing black or dark brown. The two come from the same underlying shortage of blood, and an untreated arterial ulcer can progress toward tissue death, which is the reason these wounds are assessed instead of watched.
Can I use compression stockings on an arterial ulcer?
Not without an assessment first. Compression is standard treatment for wounds caused by vein problems and can be harmful on a leg whose arteries are already narrowed. Measuring the pressure at the ankle is what determines whether compression is safe, and at what strength, so this is not a decision to make from a pharmacy shelf.
How long does an arterial ulcer take to heal?
There is no reliable single answer, because the timeline is set by the circulation and not by the wound. Progress is often slow or absent until flow improves, and can change noticeably in the weeks after a successful procedure. A wound showing no measurable change after a month is a reason to revisit the blood supply, not to change the dressing again.
Does an arterial ulcer always mean surgery?
No. Some people are managed with medication, risk factor treatment, wound care and close monitoring, particularly where the narrowing is moderate and the wound is responding. A procedure is considered when the supply is too poor for healing to occur or when the limb is judged to be at risk, and the decision is made after the circulation has been measured and imaged.
The takeaway
An arterial ulcer is a circulation problem showing itself through the skin. It shows up at the far end of the supply, on toes, heels, outer ankles and shins, it hurts more than its size justifies, it gets worse lying flat and better with the foot down, and the surrounding skin is cool, glossy and hairless with weak or absent pulses.
The decision that shapes everything else is whether flow to that foot can be improved, which is why the assessment is about arteries and the dressing conversation comes second. Two points are worth carrying away. An arterial wound can be seriously infected while looking calm, so track change instead of redness. And dry black tissue on a poorly supplied heel is sometimes protective, so it is not something to remove at home. If a foot wound has been dressed for weeks and nobody has felt for a pulse or measured a pressure, that is the appointment to ask for.
Has anyone checked the blood supply to that foot?
A wound that is not closing deserves a circulation check before another dressing is tried. An assessment can establish whether flow is the obstacle, how urgent that is, and whether onward referral to a vascular team is the right next move.
Circulation checks, protecting the wound while the flow question is answered, and working alongside vascular services where a procedure is needed are all part of how our chronic wound treatment service approaches a foot wound that will not close.
This article is general education and does not replace a clinical assessment. Whether a foot wound is arterial, and whether its blood supply can be improved, are questions answered in person by examining the limb and measuring pressures. Compression, removal of dead tissue and any change to prescribed medication are decisions for the clinician treating you, not ones to take from a web page. The urgent signs described above warrant same-day attention.
