What is calciphylaxis?

Calciphylaxis (also known as calcific uraemic arteriolopathy) is a rare condition that occurs when calcium and phosphate build up in the body. This causes chalky deposits (calcification) in the small blood vessels that supply the skin and muscles. This leads to a reduction in blood flow which causes rashes and skin ulcers.

Calciphylaxis affects around 1 in 10,000 people in the UK and occurs in 1 in 600 people receiving dialysis. It can also occur in people with CKD who are not receiving dialysis, after a kidney transplant, or very rarely, in those without kidney disease. It is usually diagnosed in late adulthood and is more common in women than men – although the reason for this is unknown.

Calciphylaxis skin ulcers images © DermNetNZ

What are the signs and symptoms of calciphylaxis?

Calciphylaxis causes rashes and ulcers to develop on the skin. These usually occur on the legs and abdomen but can affect any part of the body. The ulcers can be extremely painful and can become infected.

What causes calciphylaxis?

The exact cause of calciphylaxis is currently unknown. Risk factors that appear to make people more likely to develop calciphylaxis include:

• being overweight
• having high levels of calcium and/or phosphate in the blood
• being on dialysis for a long period of time
• having diabetes
• taking warfarin (a medication to thin the blood)
• It is sometimes triggered by a small injury such as an insect bite or a cut..

How is calciphylaxis diagnosed?

Calciphylaxis is usually diagnosed by a clinical examination. A skin biopsy may be used to look for calcification. Biopsies can affect healing however and are usually only used for unusual-looking ulcers or skin lesions.

Does calciphylaxis affect other parts of the body?

Calcification can affect other parts of the body but calciphylaxis itself is a skin condition.

Does calciphylaxis run in families?

Calciphylaxis is not a genetic condition, so it does not run in families.

How is calciphylaxis treated?

There is currently no specific treatment for calciphylaxis, although several clinical trials are researching possible options. Clinical management focuses on:

Supportive care

• pain management
• wound care – keeping any cuts clean to try and prevent infection
• good nutrition to promote healing
• psychological support that focuses on symptom management and individualised care

Managing risk factors

• dietary changes to limit high-phosphate foods such as cheese and nuts
• reviewing the dialysis plan
• changing the dialysate (the fluid used for dialysis) to one with lower calcium
• varying the sites of any daily injections, like insulin, to prevent infection

Managing medications

• Your healthcare team will review your medications to see if any need stopping or starting.

If the ulcers become infected, hospital treatment may be needed.

Where can I get more information or support about calciphylaxis?

For more information on calciphylaxis including its diagnosis, symptoms and treatment, visit the UK Calciphylaxis Study

Publication date: 09/2026

Review date: 09/2029