# Calciphylaxis > Calciphylaxis (calcific uraemic arteriolopathy) is a rare, serious condition in which calcium builds up in small blood vessels of the skin, causing painful, slow-healing ulcers. It mostly affects people with advanced kidney disease. No treatment is approved; care centres on wound care and pain control. Guide in [Wounds and ulcers](https://footanklelowerlimb.com.au/learn/topics/wounds-and-ulcers), from Foot Ankle Lower Limb: https://footanklelowerlimb.com.au/learn/calciphylaxis Reviewed by Andrew Schox, BSc(Hons) PGradDipPod MPod (Podiatrist) on 11 November 2026. Next review by 11 November 2027. - **It's rare but serious.** Calcium blocks small blood vessels in the skin and fat, causing painful ulcers that heal slowly. - **It mostly affects people with advanced kidney disease,** especially those on dialysis. - **Severe pain is a hallmark,** and it can start before any skin changes are visible. - **No treatment is approved,** so care combines wound care, pain control and protecting the skin. - **Infection of the wounds is the main danger.** ## What is calciphylaxis, and how common is it? Calciphylaxis (also called calcific uraemic arteriolopathy, or CUA) is a rare but serious condition [1]. Calcium builds up in the small blood vessels of the skin and fat, which limits blood flow and causes painful skin ulcers [2]. The wounds can be slow to heal and may become infected [3]. It mostly affects people with advanced chronic kidney disease, most commonly stage 4 or 5, and especially people on dialysis [4]. About 1–4% of people on dialysis are reported to be affected [5]. It's reported more often in people on peritoneal dialysis than in people on haemodialysis [6]. It can also occur with normal kidney function [7]. Calciphylaxis is life-threatening [4]. ## What causes it, and who gets it? The exact cause isn't known [1]. Calcification and clotting in the small blood vessels are thought to be involved [2]. Factors commonly linked with a higher risk are diabetes, higher body weight, low blood albumin (a blood protein), abnormal calcium and phosphate levels, use of warfarin-type blood thinners (vitamin K antagonists) and being female [1]. Anaemia, inflammation, smoking, high blood pressure and less effective dialysis have also been named, but the links are less consistent [1]. These are links, not proven causes. Warfarin is described as a recognised risk factor [8], though studies of it have been inconsistent [9]. A painful skin rash in someone taking warfarin can be a sign of calciphylaxis [10]. Using warfarin with extreme caution is advised in advanced kidney disease, especially when blood vessel calcification is known [11]. Evidence on whether stopping it helps is limited, so warfarin shouldn't be stopped or changed without medical advice [9]. ## What does it look and feel like, and how is it diagnosed? Pain is the hallmark, and it can be very hard to control [12]. It can come before any skin changes [2] and be out of proportion to how the skin looks [13]. Early skin changes are tender, dusky purple-pink lumps or plaques under the skin [13]. The skin may show net-like mottling, purple patches or hard nodules, and it often blisters and breaks down, sometimes with infection [9]. Ulcers commonly have black dead tissue (eschar) on them [9]. They mostly appear on fatty areas such as the abdomen and thighs [12]. > [!tip] Try this > Keep a short note of when the pain began, where it is and any skin changes, with dates. Pain can come before changes you can see, so a note helps show how things have progressed. Some features mark the condition as becoming more serious: worsening pain, skin breakdown or ulceration, signs of infection (redness, warmth, pus or fever) and new or enlarging nodules [7]. Infected ulcers can progress to sepsis (a dangerous whole-body reaction to infection) [2]. Painful lesions can also turn into dead (necrotic) or gangrenous ulcers, and amputation is sometimes needed [5]. Early lesions can look like other problems, such as nodules, purpura (purple, bruise-like spots) or cellulitis (a skin infection), so they are easily overlooked [8]. Calciphylaxis is usually suspected in people at high risk who have extensive painful ulcers with a black scab-like covering, once other causes have been ruled out [8]. There's no standard way to diagnose it. Some authorities say it is mainly a clinical diagnosis, while others rely on a skin biopsy (a small skin sample) [1]. A biopsy can help when the picture is unusual or overlaps with other skin conditions [1]. It can also cause new or worse lesions, infection, bleeding or tissue death, so its risks are weighed first [9]. ## What helps first? No treatment has been proven to work, and none is approved for calciphylaxis [14]. Because the cause is unknown, treatment is difficult and often trial-and-error [5]. Care usually combines decalcification (treatment aimed at reducing the calcium), wound care and pain control [15]. Pain relief needs extra care in kidney disease, because many painkillers are cleared by the kidneys and several different medicines are often needed [3]. Pain is often severe and under-treated, and some people have been given only basic painkillers such as paracetamol [16]. Protecting the skin is something you can do yourself. That means avoiding knocks, pressure and injury to affected skin, and varying where injections (such as insulin) are given [9]. How much this changes outcomes isn't clear yet [9]. ## What helps if that isn't enough? There's no good evidence that any particular option works when first-line care falls short, and no therapy is approved [14]. Lesions can keep developing despite treatment, and management may take many months [3]. What is supported is ongoing wound care, careful pain control and protecting lesions from injury [15][9]. Delayed diagnosis, wound care that varies from place to place and a lack of emotional support are also common difficulties [16]. ## What is the outlook, and can it come back? The outlook is serious. Reported death rates within a year of diagnosis range widely, from 30% to 80%, and in some reports more than half of people die within the first year [2]. Deaths are largely driven by wound infections and cardiovascular events (heart and blood vessel problems) [17]. How often calciphylaxis comes back after healing isn't clear yet. Ideas for lowering risk that are still being evaluated, and aren't proven, include making dialysis as effective as possible, managing high blood pressure, anaemia and diabetes, cautious weight loss if overweight, stopping smoking, avoiding substances that can harm the liver, using another kind of blood thinner in place of warfarin-type medicines where possible, and keeping calcium and phosphate levels in balance [1]. ## Common questions ### Can calciphylaxis be cured? No treatment has been proven to work or approved, so there is no reliable cure. Care usually combines wound care, pain control and treatment aimed at reducing calcium. Lesions can keep developing despite treatment, and management may take many months. The aim is to protect the skin, control pain and watch for infection. ### Why is calciphylaxis so painful? The pain is believed to come from both reduced blood supply to the skin (ischaemia) and nerve involvement. Severe pain is a nearly universal feature, it can appear before skin changes, and it can be extremely hard to control. Many painkillers need extra care in kidney disease, which makes pain relief more complicated. ### Is calciphylaxis the same as calcific uraemic arteriolopathy? Yes. Calciphylaxis, calcific uraemic arteriolopathy and CUA are different names for the same condition, in which calcium builds up in small blood vessels of the skin and fat. It is also written as calcific uremic arteriolopathy, using the American spelling. ## Further reading - [Calciphylaxis on Clindice](https://clindice.com/calciphylaxis) - [What Is Calciphylaxis?](https://my.clevelandclinic.org/health/diseases/22359-calciphylaxis), Cleveland Clinic - [Calciphylaxis](https://www.ouh.nhs.uk/media/xpilerym/102692calciphylaxis.pdf), NHS - [Abstract Book](https://foundationprogramme.nhs.uk/wp-content/uploads/sites/2/2025/02/NFDPD-2025-Abstract-Book.pdf), NHS - [Shared Care Guideline for Refractory Secondary Hyperparathyroidism (SHPT) in adult patients with End Stage Renal Disease (ESRD)](https://primarycare.northeastlondon.icb.nhs.uk/wp-content/uploads/2026/09/SCG-for-Refractory-Secondary-Hyperparathyroidism-SHPT-in-adult-patients-with-End-Stage-Renal-Disease-.pdf), NHS - [Going home with a vascular catheter](https://www.uhcw.nhs.uk/download/clientfiles/files/Patient%20Information%20Leaflets/Medicine/Renal/Going%20home%20with%20a%20vascular%20catheter.pdf), NHS ## Sources 1. Calciphylaxis in chronic kidney disease: a systematic review of pathomechanisms and risk factors for calcific uremic arteriolopathy · Søndergaard C, Nagarajah S, Shen J et al. · Renal Failure · 2026. https://doi.org/10.1080/0886022x.2026.2710397 2. Calciphylaxis in End-Stage Renal Disease: A Rare Condition With High Mortality · Bachu R, Patel TH, Hemmings S · Cureus · 2022. https://doi.org/10.7759/cureus.26752 3. Redirecthandler · ouh.nhs.uk. https://www.ouh.nhs.uk/redirecthandler/?id=102692calciphylaxis&type=patientleaflet 4. The use of cinacalcet for the treatment of calciphylaxis in patients with chronic kidney disease: A comprehensive review · Deen J, Schaider H · The Australasian Journal of Dermatology · 2019. https://doi.org/10.1111/ajd.12992 5. Calciphylaxis: an enigma to the nephrologist · Barbera V, Di Lullo L, Otranto G et al. · Giornale Italiano di Nefrologia · 2012. https://pubmed.ncbi.nlm.nih.gov/23229665/ 6. Sodium Thiosulfate for Calciphylaxis Treatment in Patients on Peritoneal Dialysis: A Systematic Review · Gossett C, Suppadungsuk S, Krisanapan P et al. · Medicina (Kaunas, Lithuania) · 2023. https://doi.org/10.3390/medicina59071306 7. Calcinosis Cutis · Le C, Sathe NC · NCBI Bookshelf · 2023. https://www.ncbi.nlm.nih.gov/sites/books/NBK448127/ 8. Early diagnosis strategy of calciphylaxis in dialysis patients · Liu Y, Zhang X · Renal Failure · 2023. https://doi.org/10.1080/0886022x.2023.2264407 9. Calciphylaxis: risk factors, diagnosis, and treatment · Nigwekar SU, Kroshinsky D, Nazarian RM et al. · American Journal of Kidney Diseases · 2015. https://doi.org/10.1053/j.ajkd.2015.01.034 10. Warfarin: medicine used to prevent and treat blood clots · NHS. https://www.nhs.uk/medicines/warfarin/ 11. Multimodality approach to treat calciphylaxis in end-stage kidney disease patients · Lajoie C, Ghanemi A, Bourbeau K et al. · Renal Failure · 2023. https://doi.org/10.1080/0886022x.2023.2256413 12. Pain management in patients with end-stage renal disease and calciphylaxis- a survey of clinical practices among physicians · Chinnadurai R, Sinha S, Lowney AC et al. · BMC Nephrology · 2020. https://doi.org/10.1186/s12882-020-02067-2 13. ACD A-Z Skin - Calciphylaxis · ACD. https://www.dermcoll.edu.au/atoz/calciphylaxis/ 14. Intravenous Sodium Thiosulphate for Calciphylaxis of Chronic Kidney Disease: A Systematic Review and Meta-analysis · Wen W, Portales-Castillo I, Seethapathy R et al. · JAMA Network Open · 2023. https://doi.org/10.1001/jamanetworkopen.2023.10068 15. Navigating Calciphylaxis in End-Stage Renal Disease: A Case Report Highlighting the Complexities of Pain Control and the Need for Greater Clinical Vigilance · Lau RCN, Whitwell BL, Chinawanitkit C et al. · Cureus · 2025. https://doi.org/10.7759/cureus.96962 16. Calci-E · Health Research Authority. https://www.hra.nhs.uk/planning-and-improving-research/application-summaries/research-summaries/calci-e/ 17. Circulating Levels of Inorganic Pyrophosphate Influence the Risk and Clinical Outcomes in Calciphylaxis · Nigwekar SU, Chewcharat A, O'Brien K et al. · JACC · 2026. https://doi.org/10.1016/j.jacadv.2026.103205 --- This is general information, not advice about your own situation. To discuss your issues, book with one of our podiatrists. In an emergency, call 000.