Calcinosis cutis is the accumulation of calcium salt crystals in your skin. The calcium deposits are hard bumps that don’t dissolve. The shape and size of the lesions vary.
This is a rare condition that has many different causes. These range from infection and injury to systemic diseases like kidney failure.
Often calcinosis cutis has no symptoms. But in some cases, it can be very painful. Treatments are available, including surgery, but the calcium lesions may recur.
Types of calcinosis cutis
There are five subtypes of calcinosis cutis:
- Dystrophic calcification. This is the most common type of calcinosis. It occurs where the skin has been damaged or inflamed. It doesn’t involve abnormal levels of calcium or phosphorus in the body.
- Metastatic calcification. This occurs in people whose calcium and phosphorus levels are abnormally high.
- Idiopathic calcification. This type of calcinosis cutis has no evident cause. It usually occurs in one area of the body only.
- Iatrogenic calcification. This type of calcinosis cutis results from a medical procedure or therapy, usually accidentally. For example, newborns can have an iatrogenic calcification on the heel, resulting from heel sticks to take blood.
- Calciphylaxis. This rare and serious type of calcinosis cutis usually occurs in people who have kidney failure, have received a kidney transplant, or are on dialysis. It affects the blood vessels in the skin or fat layer. Calcium and phosphate levels in the body are abnormal.
Symptoms of calcinosis cutis
The appearance and location of calcinosis cutis depend on the underlying cause. The lesions are usually hard, whitish-yellow bumps on the skin surface. They start slowly and vary in size.
The lesions may have no symptoms, or they may be severe, painful, or oozing a whitish substance. In rare cases, a lesion may become life-threatening.
Here are areas where the lesions typically appear in each of the subtypes of calcinosis cutis:
- Dystrophic calcification. The bumps occur in the area of tissue damage. Typical areas are forearms, elbows, fingers, and knees. With lupus, the lesions occur on hands and feet, the buttocks, and under lupus lesions.
- Metastatic calcification. Bumps are located symmetrically around joints: knees, elbows, or shoulders. They may also form around internal organs, such as lungs, kidneys, blood vessels, or the stomach. Lesions around joints can limit mobility as the skin stiffens.
- Idiopathic calcification. This usually affects only one area of the body. It can occur around major joints, the scrotum, the head, the breasts, the penis, the vulva, or hands and feet. In children, it may be on the face. The lesions may have white discharge.
- Iatrogenic calcification. The lesion appears at the site of a medical or therapeutic procedure that pierces the skin.
- Calciphylaxis. Skin lesions are usually on the legs or trunk, especially the fatty areas such as breasts, buttocks, and stomach. The lesions are mottled looking and painful. They can become ulcers that don’t heal, or they can develop gangrene. The lesions may be accompanied by other symptoms, such as fatigue and weakness.
Causes of calcinosis cutis
Calcinosis cutis is rare but has a wide range of causes, depending on the subtype:
In general, tissue damage leads to phosphate proteins released by dying cells which then calcify, forming calcium salts. The tissue damage can come from:
- connective tissue diseases such as lupus, systemic sclerosis, or dermatomyositis
When the body’s calcium phosphate is abnormally high, it produces calcium salts that form nodules on the skin. Causes of the abnormal levels of calcium and phosphate are:
- chronic kidney failure (the most common cause)
- too much vitamin D
- hyperparathyroidism (an enlarged parathyroid gland overproduces thyroid hormone)
- sarcoidosis (groups of inflammatory cells form in the lungs, lymph nodes, skin, and other parts of the body)
- milk-alkali syndrome (too much calcium from foods or antacids)
- bone diseases, such as Paget’s disease
Unlike the first two types of calcinosis cutis, idiopathic calcification occurs with no underlying tissue damage and no abnormal levels of calcium or phosphorus. Idiopathic means “no known cause.” There are three types:
- familial nodules, which usually appear in healthy teenagers or young children
- subepidermal nodules, which appear just below the skin
- nodules on the scrotum
The cause of iatrogenic calcification is a medical procedure that accidentally leads to calcium salt deposits as a side effect. The mechanism for this isn’t known. Some of the procedures involved are:
- administration of solutions containing calcium and phosphate
- prolonged contact with saturated calcium chloride electrode paste during an electroencephalograph or electromyograph
- intravenous calcium gluconate, calcium chloride, and para-aminosalicylic acid in tuberculosis treatment
- heel sticks in newborns
The cause of calciphylaxis remains uncertain. It’s very rare, although some of the associated factors are common:
- chronic kidney failure
In combination with scleroderma
Calcinosis cutis often occurs along with systemic sclerosis (scleroderma). It’s found especially in the limited form of this disease, known as limited cutaneous systemic sclerosis (CREST).
An estimated 25 to 40 percent of those with CREST syndrome will develop calcinosis cutis after 10 years.
The lesions usually appear around fingers and elbows and may break open and leak a thick white material.
Diagnosis of calcinosis cutis
Determining the type of calcinosis cutis you have is important in deciding the appropriate treatment. Your doctor will examine you and take your medical history and ask you questions about your symptoms.
The doctor will likely order several laboratory tests to determine the underlying cause of your calcinosis cutis:
- blood tests to see if your calcium and phosphate levels are abnormally high, to look for markers for lupus and possible tumors, and to rule out abnormal parathyroid and vitamin D levels
- metabolic tests to rule out kidney problems
- X-rays, CT scans, or bone scans (scintigraphy) to look at the extent of the calcification
- biopsy of the lesions
- other specialized tests to check for dermatomyositis (an inflammatory disease) and milk-alkali syndrome
A new technology under development to aid diagnosis is advanced vibrational spectroscopy. This diagnostic technique uses Fourier transform infrared (FT-IR) or Raman spectroscopic analysis. It rapidly identifies the chemical composition of the calcinosis cutis lesions. It can also predict disease progression.
Treatment of calcinosis cutis
Treatment for calcinosis cutis depends on the underlying disease or cause.
A variety of drugs can be tried to treat the lesions, but their success has been spotty.
For smaller lesions, drugs that may help include:
- intravenous immunoglobulin (IVIG)
For larger lesions, drugs that may help include:
- aluminum hydroxide
A 2003 study reported that a low dose of the antibiotic minocycline was effective in relieving the pain and extent of lesions in people with CREST syndrome. Topical sodium thiosulfate may also be useful.
If your lesions are painful, get infected often, or impair your functioning, your doctor may recommend surgery. But the lesions may recur after surgery. It’s recommended that surgery starts with a small section of a lesion.
A proposed new treatment is hematopoietic stem cell transplantation (HSCT), which replaces a person’s blood production cells. This has been used to treat some autoimmune diseases.
Laser therapy and shock wave lithotripsy (an ultrasound therapy used to break up kidney stones) are also possible treatments.
Outlook for calcinosis cutis
The outlook for calcinosis cutis depends on its underlying disease or cause, and the severity of your lesions. Current treatments may help, and new therapies are being developed. Talk to your doctor about how to relieve your symptoms and treat the root of the problem.