Calcinosis (Calcinosis Cutis)

What calcinosis is

Calcium and phosphate normally stay dissolved in blood and tissue fluid. Calcinosis occurs when they crystallize as calcium hydroxyapatite in the skin, fat, muscle or around joints. This happens either because the tissue is damaged and attracts calcium, or because blood levels of calcium or phosphate are high enough for crystals to form in healthy tissue.

Types of calcinosis

Dystrophic calcinosis

The most common type. In systemic sclerosis, particularly the limited form once called CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal problems, sclerodactyly, telangiectasia), deposits form on the fingertips, forearms, elbows and knees. In dermatomyositis, especially in children, extensive deposits can form in the skin and muscle, sometimes in sheets. Lupus causes calcinosis less often.

Metastatic calcinosis

In chronic kidney disease, the kidneys cannot remove phosphate, and calcium-phosphate balance is disrupted. Deposits form around joints, in blood vessels and in the skin. Hyperparathyroidism and excess vitamin D also raise calcium.

Calciphylaxis

A rare, serious condition mostly in people on dialysis, in which calcium blocks small blood vessels in the fat and skin. It causes extremely painful purple patches that turn into black, dead skin ulcers. It needs urgent specialist care.

Symptoms

• firm, white or yellowish lumps or plaques under the skin
• pain or tenderness, especially when deposits press on nerves or sit over fingertips, elbows or knees
• skin breaking down over the lump, with a white, chalky or toothpaste-like discharge
• infection of open deposits
• stiffness and reduced movement when deposits are near joints
• in calciphylaxis: severe pain, purple net-like discoloration and black ulcers, usually on the thighs, belly or buttocks

Diagnosis

A doctor will examine the deposits and ask about connective tissue disease, kidney disease, medicines and injuries. Tests include:

• X-rays or CT scans: show calcium clearly and how extensive it is
• blood tests: calcium, phosphate, parathyroid hormone (PTH), vitamin D and kidney function
• autoimmune antibodies (such as antinuclear antibodies and anti-centromere antibodies) if a connective tissue disease is suspected
• skin biopsy when the diagnosis is unclear or for suspected calciphylaxis

Treatment

Treating calcinosis is challenging, and no single medicine works for everyone.

Treat the underlying cause

• In kidney disease: lowering phosphate with diet and phosphate binders, controlling PTH, and adjusting dialysis.
• Surgery for hyperparathyroidism.
• Controlling active dermatomyositis with immune-suppressing treatment, which can stop new deposits, especially in children.
• Treating Raynaud's phenomenon, as poor blood flow may contribute in scleroderma.

Medicines with some evidence

• Diltiazem, a calcium channel blocker
• Sodium thiosulfate, applied as a cream, injected into lesions, or given IV for calciphylaxis
• Bisphosphonates
• Colchicine and minocycline for inflammation around deposits
• Warfarin in low doses, or newer agents, in selected cases

Evidence for each is limited, so specialists tailor treatment.

Procedures

• Surgical removal of painful, ulcerated or function-limiting deposits
• Shock wave lithotripsy to break up deposits
• Laser treatment for small superficial deposits
• Wound care and antibiotics for infected ulcers

Pain relief

Pain relievers, protective padding and physical therapy help daily function.

Outlook

Calcinosis tends to be long-lasting. Some deposits shrink slowly, especially in children with dermatomyositis once the disease is controlled, and metastatic calcinosis may improve when calcium and phosphate are normalized. Calciphylaxis has a serious outlook and needs urgent multidisciplinary care.

Frequently asked questions

What is calcinosis cutis?

Calcinosis cutis is calcium deposited in the skin, forming hard white or yellow lumps. It is most often linked to scleroderma, dermatomyositis, lupus, kidney failure or previous skin injury. The deposits can be painful and may break through the skin.

What causes calcium deposits in the skin?

Calcium deposits form when damaged tissue attracts calcium (dystrophic calcinosis), as in scleroderma or after injury, or when blood calcium or phosphate levels are high (metastatic calcinosis), as in kidney failure or hyperparathyroidism.

Is calcinosis related to scleroderma?

Yes. Calcinosis is common in systemic sclerosis, especially the limited type once called CREST syndrome, where the C stands for calcinosis. Deposits often form on the fingertips, forearms and elbows and can be painful.

How is calcinosis treated?

Treatment focuses on the underlying cause, such as controlling dermatomyositis or lowering phosphate in kidney disease. Medicines such as diltiazem or sodium thiosulfate help some people. Painful or ulcerated deposits can be removed surgically.

Can calcium deposits in the skin go away?

Sometimes. Deposits may slowly shrink once the cause is controlled, especially in children with dermatomyositis. Many deposits remain and are managed with pain relief, wound care and, when needed, surgical removal.