The foot is warm. It is a bit swollen, slightly pink across the top, and the shoe still goes on if you loosen the laces. There was no fall, no twist, nothing you can point to. It does not really hurt, not in the way a broken bone is supposed to hurt, so you walk on it. You walk on it to the shops, around the garden, up and down the stairs. Three weeks later the arch looks flatter than the other one, and the shoe no longer goes on at all.
That sequence has a name. It is called Charcot neuro-osteoarthropathy, or Charcot foot, and it is one of the few conditions in which walking normally is the thing doing the damage. It is also, by the measure of Ireland’s own health service documents, something that should put you in front of a hospital foot team within twenty-four hours. Whether that actually happens tends to depend on which HSE page you, or your GP, happen to be reading.
TL;DR
- Charcot foot is a hot, red, swollen foot in someone with nerve damage, usually from long-standing diabetes. The bones fracture and the joints dislocate while the person keeps walking, because the nerve damage removes the pain that would normally stop them.
- It is missed more often than it is caught. A systematic review found 53.2% of cases were misdiagnosed first, with an average of 86.9 days from the first symptom to the right answer. Cellulitis, gout, a sprain and a clot are the usual wrong answers.
- A normal X-ray does not rule it out. In early (stage 0) disease the X-ray is clear and only MRI shows the bone injury underneath.
- Ireland’s Diabetic Foot Model of Care classes “an unexplained hot, red, swollen foot with or without pain” as active foot disease, which means referral within 24 hours to a hospital multidisciplinary foot team. The HSE’s public-facing foot-care page files unexplained foot swelling under non-urgent advice.
- Treatment is offloading, not tablets. International guidance says to put the leg in a knee-high immobilising device as soon as the condition is suspected, before the scans confirm anything, and says plainly not to use bisphosphonates or denosumab for it.
What is actually happening inside the foot
Charcot foot needs two ingredients. The first is peripheral neuropathy: nerve damage that dulls or removes protective sensation in the feet. The second is ordinary, unremarkable use of the foot. Together they produce something researchers have described as an imperfect storm, a reparative process that turns on itself.
In a foot with normal sensation, a small fracture announces itself loudly and you stop. In a neuropathic foot it registers as nothing much, so you keep weight-bearing. The bone, already fragile from increased local blood flow and bone resorption, fractures further. Ligaments stretch, joints slip out of line, and the architecture of the midfoot gives way. The arch drops, sometimes until the sole becomes convex rather than concave, which is why clinicians call a late Charcot foot a rocker-bottom deformity. The pressure points end up in all the wrong places, and an ulcer is close behind.
The counter-intuitive detail is the pain. People often feel something, an ache or a heaviness, but nothing like the pain a fracture would normally produce. Irish and international guidance both make the same allowance: the hot, swollen foot counts “with or without pain”. Waiting for it to hurt properly is waiting for a signal the nerve damage has already deleted.
Who it happens to
Most cases occur in people with long-standing diabetes and established neuropathy, and most present in their fifties and sixties, with recent studies putting the mean age at around 58 or 59. It is uncommon rather than rare: a Danish national register study found Charcot foot in 0.56% of people with a diabetes code, an incidence of roughly 7.4 per 10,000 person-years.
Those numbers almost certainly understate it, because a condition that is routinely misdiagnosed is also routinely uncounted. Around 30% of cases involve both feet, which matters for anyone comparing one foot against the other, and Charcot joints can occur with other causes of severe neuropathy too. Poor long-term glucose control, longer diabetes duration, obesity and kidney disease all raise the risk.
If you have been told at any point that you have reduced sensation in your feet, you are in the group this article is written for. Our guide to peripheral neuropathy after 50 covers how that testing is done and what the results mean.
Why it gets missed
A hot, red, swollen foot has a long list of common causes. Cellulitis looks like it, so do gout, a sprain, a clot and inflammatory arthritis, and Charcot foot sits at the bottom of that list in most people’s minds.
The published evidence on delay is uncomfortable reading. A 2022 systematic review in the Journal of Foot and Ankle Surgery pooled the available studies and found that 53.2% of people with Charcot osteoarthropathy were misdiagnosed before the correct diagnosis was made, with an average delay from symptom onset of 86.9 days. The confidence intervals around both figures were wide, which tells you how little good data exists, but the direction is not in doubt: most people spend weeks to months walking on a foot that is quietly coming apart.
Imaging contributes to the problem. Plain X-rays are the right first test, ideally weight-bearing and on both feet for comparison. But early disease, what clinicians call stage 0, produces a normal X-ray with abnormal MRI underneath: bone marrow oedema and microfractures that plain film cannot see. A clear X-ray in the first weeks is reassuring to exactly the wrong degree, and the international guideline is explicit that MRI should follow a normal X-ray when the suspicion is there.
The simplest sign is temperature. Healthy feet are broadly symmetrical in skin temperature; an active Charcot foot is not. A difference of around 2°C between the affected foot and the same spot on the other one has been used as a threshold for decades, though the 2023 international guideline looked for studies validating it against imaging and could not find them. Raised temperature alone is sensitive but not specific, and has to be read alongside the swelling and redness. In practice that is less technical than it sounds: compare the two feet with the back of your hand, and if one is noticeably hotter and more swollen for no reason you can name, that is the finding worth reporting.
The Irish part: two documents, two different levels of urgency
Here is where Ireland’s own paperwork disagrees with itself. The HSE’s Diabetic Foot Model of Care, published by the National Clinical Programme for Diabetes in June 2021 and updated in May 2026, sorts every person with diabetes into one of five foot-risk categories: low risk, moderate risk, high risk, in-remission, and active foot disease. The active foot disease category contains five triggers. One is a current foot ulcer. One is spreading infection. One is critical limb ischaemia. One is “suspicion of an acute Charcot arthropathy”. And the fifth, written out in full in the national screening protocol, is “an unexplained hot, red, swollen foot with or without pain”.
The management plan attached to that category is not ambiguous. Refer within 24 hours to the hospital multidisciplinary foot team, with the referral triaged by a clinical specialist or senior podiatrist aiming to review the person within 24 hours, or the next working day. The national screening and risk stratification form that accompanies the model of care has a tick box, printed on the page, reading “Suspected Charcot”.
Now read the HSE’s public page for people living with type 2 diabetes, Looking after your feet. It tells you to examine your feet every day, which is good advice. Then it offers a box headed “Non-urgent advice”, and in that box it says to contact your GP or practice nurse if you notice an unexplained foot swelling, or a change in colour or sensation.
The same clinical finding is a same-day hospital referral in the document written for clinicians and a non-urgent GP contact in the one written for patients. The patient page is a general foot-care page and is not trying to be a Charcot pathway. But the practical effect, for someone with neuropathy reading it on a Sunday evening with one foot visibly bigger than the other, is false reassurance that this can wait for the next free appointment.
The stakes are set out in the model of care itself. It opens by citing Irish research showing that a person with diabetes here is 22 times more likely to undergo a non-traumatic amputation than someone without. Its foreword holds up RetinaScreen, Ireland’s national diabetic eye screening programme, as what a co-ordinated national approach achieved for sight, and notes that nothing equivalent exists for limb loss. It also asks for investment in a National Diabetes Registry so prevalence can be tracked. Five years on, that remains an ask rather than a fact, which is why nobody can tell you how many Charcot feet there are in Ireland in a given year.
What treatment actually involves
The treatment for active Charcot foot is to take the load off it, for months. That is the whole of it, and it is more demanding than it sounds.
The 2023 guideline from the International Working Group on the Diabetic Foot gives a strong recommendation to begin knee-high immobilisation promptly while the diagnostic tests are still being arranged. Not after the MRI. While waiting for it. The preferred device is a total contact cast, or a knee-high walker made non-removable; a removable knee-high boot worn at all times is the third choice. Below-the-ankle options, the post-operative sandal or surgical shoe, are specifically advised against, because they do not immobilise the joints that are failing.
Resolution is measured in months. The guideline prefers the word “remission” to “healed”, because resuming normal walking in unsuitable footwear can reactivate the process. One Canadian cohort found around 70% of feet settled without surgery at an average of about six months, with roughly a quarter needing an operation and 8% ending in amputation.
What does not work is medication. The same guideline carries a strong recommendation not to use alendronate, pamidronate, zoledronate, calcitonin, parathyroid hormone or methylprednisolone for active Charcot foot, and advises against denosumab. Vitamin D and calcium are addressed only as ordinary supplementation for people who need them.
The consequences of leaving it are why the urgency exists. Published series suggest up to 80% of Charcot feet eventually develop an ulcer, with a high risk of major amputation, and five-year mortality in cohort studies sits between about 13% and 14%, reported as high as 28% in some groups.
What to do, practically
Learn your foot-risk category. At your annual diabetes foot check, in general practice for type 2 diabetes or the hospital clinic for type 1, you are being sorted into low, moderate, high risk, in-remission or active foot disease. Ask which one you are and ask for it to be written down. The category determines everything that follows, including how often a podiatrist should see you.
If one foot goes hot and swollen, treat it as today’s problem. Ring the GP or practice nurse and say the specific sentence: “I have diabetes and nerve damage in my feet, and one foot is hot, red and swollen with no injury. Could this be a Charcot foot?” Naming the condition moves the question from “what kind of infection is this” to “does this need the foot team”. If you already attend a hospital foot clinic or a community podiatrist, ring them directly.
Keep the weight off it until someone has looked. Not heroic bed rest, but not a normal day on your feet either. Every week of walking on an active Charcot foot is a week of further bone damage, and that damage does not reverse.
Do not let a normal X-ray close the file. If the foot is still hot and swollen a fortnight later and the X-ray was clear, that is the point to ask about MRI.
Know how to get podiatry. Medical card holders can access HSE podiatry through their local primary care centre on GP referral, and waiting times vary a great deal by area, so ask early rather than when something is already wrong. Private podiatry typically runs from about €40 to €70 a visit and is covered in part by many health insurance policies.
The part nobody warns you about
Several months in a knee-high cast changes a life in ways that have nothing to do with bones. You cannot drive. Stairs become a project. Showering requires equipment. Research into how people experience an acute Charcot foot describes feeling trapped at home and cut off from hobbies and social roles, with some calling it closer to a loss of identity than an inconvenience.
That is worth planning for rather than enduring. An occupational therapy assessment can get the right aids and rails in place early, and if longer-term changes are needed at home, the housing adaptation grant schemes exist for exactly this, though they are paid on completion, so applying early matters. Reduced mobility also raises the risk of a fall, and our guides to falls prevention and getting up off the floor are worth reading before you need them.
The thing to hold on to is that the outcome genuinely does turn on the first fortnight. A Charcot foot caught at stage 0, when the X-ray is still clear and the shape of the foot is still normal, can go into remission with the foot it started with. One caught after the midfoot has collapsed usually means custom footwear for life and often surgery. The gap between those two outcomes is measured in weeks of walking, which is why the swollen foot that does not hurt deserves more alarm than it usually gets.
At Críonna Health we write about the conditions that hide behind “it’s probably just my age”, because ageing well in Ireland depends as much on knowing which symptom to escalate as on anything else. A hot, swollen foot with no explanation is one of them. It is not a sprain, and it is not something to see how it goes with.
This article is general health information and is not a substitute for individual medical advice. If you have diabetes and one foot becomes hot, red or swollen without an obvious cause, contact your GP, practice nurse or diabetes foot team without delay.
📷 Photo by Youcef Chenzer on Unsplash
