What is calciphylaxis?
Calciphylaxis is a rare and severe condition mostly seen in people with kidney problems, especially those receiving dialysis. It happens when calcium products build up in the small blood vessels in and around the skin, blocking the flow of blood – this is a process known as ‘calcification’. As a result, the skin and underlying tissues do not receive enough blood flow, stopping adequate oxygen from reaching the skin. This leads to painful skin ulcers that are prone to serious infection.
Causes of calciphylaxis
The exact cause of calciphylaxis isn’t fully understood; it remains unknown why some people get the condition and others do not. In addition to kidney disease, possible risk factors (things that increase the chances of a person developing the condition) are:
- Being overweight
- Use of certain medications, such as warfarin
- Female gender: women are more commonly affected by calciphylaxis than men
- Hyperparathyroidism (high parathyroid hormone level in the blood): an overactive parathyroid gland can disrupt the balance of calcium and phosphate in the body
- High levels of calcium and/or phosphate in the blood.
Calciphylaxis symptoms
Symptoms include very painful skin sores, which may begin as purple or red in appearance (before becoming black) and most commonly occur around the abdomen and legs but can affect any area of the body.
The skin ulcers put people at high risk of developing infections which can lead to hospital admission.
People with calciphylaxis can feel tired, weak, and unwell due to pain (which can be severe), possibly infection and from side effects of treatments.
Calciphylaxis diagnosis
There is no simple test for calciphylaxis. Diagnosing calciphylaxis typically involves a clinical evaluation (examining the symptoms and reviewing the medical history). Sometimes a skin biopsy can be taken, where a small sample of the affected skin is removed and checked under a microscope to look for evidence of calcium in the blood vessels, but this is not always needed.
Calciphylaxis treatment
If you notice symptoms of calciphylaxis, it is important to let your kidney team know. There is currently no specific treatment, but healthcare providers will try to individualise care to address any underlying causes, such as improving calcium and phosphate levels, or stopping medications such as warfarin.
If you are on dialysis your medical team might suggest that the amount you have be increased. Wound care and medications to help manage pain and treat, or prevent, infections will also be given. There are a number of new treatments being investigated that might benefit this condition so you may also be invited to take part in a research trial. Even if you are not, you should feel able to ask you doctors about being in a research study (see below).
If appropriate, kidney dietitians can provide guidance on how to adjust your diet to control your phosphate intake. Whilst some people make a good recovery, sadly around 5 in 10 people with the condition will die within a year of diagnosis.
Useful resources
Patient support : At present there is not a patient support group for calciphylaxis; we hope this will change in the near future.
The National Kidney Federation have developed a leaflet for patients: Download.ashx (kidney.org.uk)
Rare Renal Disease Registry: There is a need for greater awareness and support. If you have been diagnosed with the condition and would be willing to share your story or act a patient representative then please do get in touch with the Rare Renal Team: https://ukkidney.org/rare-renal/contact-us/form
Reviewed October 2023
Researcher spotlight
The rarity of the condition has limited the ability to do large enough research studies that can clearly demonstrate the benefit of treatments.
Professor Smeeta Sinha from Salford Royal Hospital, and Dr Sharon Huish from the University of Exeter have been awarded a grant of £27,000 from Kidney Research UK and Kidney Wales to conduct in-depth interviews of people with calciphylaxis, their families and carers to better understand the lived experience of this condition. The study will investigate how people with calciphylaxis felt about their diagnosis, treatments, interactions with their healthcare teams, and the support that they were offered, and identify areas requiring improvement.
The team aim to improve care for those with calciphylaxis and to increase awareness. Additionally, they aim to standardise patient information on calciphylaxis, helping all patients to deal with diagnosis and management. New information will be designed to be accessible to different patient groups, with content based on the experiences and needs of those living with calciphylaxis.
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