Dystrophic calcinosis is the abnormal collection of calcium salts in or under the skin and in muscles or tendons, even when levels of calcium in the blood are normal. It occurs in some patients with dermatomyositis. These lesions may also appear in patients with overlapping autoimmune diseases, including systemic sclerosis, systemic lupus erythematosus, and mixed connective tissue disease.
Calcinosis appears more often in juvenile dermatomyositis, where as many as 70% of JDM patients may be affected. In adults with myositis, about 20% of patients report this complication. Calcinosis usually appears within the first three years after diagnosis, however, it is sometimes the first symptom to appear. Other times, it doesn’t occur until many years after diagnosis.
Calcinosis appears as hard, irregular nodules (lumps) in or under the skin in any area of the body. These lumps can be especially uncomfortable when they appear on the face, around joints, or on pressure points, such as the buttocks, feet, or wrists. The nodules can cause functional disability, contractures, skin ulcers, and pain. Needless to say, calcinosis can have a significantly negative impact on the patient’s quality of life.
Why these nodules develop is still not well-understood. It is hypothesized that tissue damage from inflammation and the blood vessel changes of dermatomyositis may lead to these abnormal mineral formations in the skin.
Treatment of dystrophic calcinosis can be challenging. There is no treatment that is effective for everyone. Inadequate initial treatment of dermatomyositis may play a role in the development of calcinosis lesions. Therefore, early and aggressive treatment of the underlying muscle and skin disease with immunosuppression is strongly recommended.
In addition, increasing blood flow to the extremities, through smoking cessation, decreasing stress, and limiting exposure to cold, may be helpful. Appropriate sun-protection is always important in dermatomyositis, but it may also prevent calcinosis, since sun exposure can stimulate the immune system, which may contribute to calcinosis.
Smaller lesions may respond to medications such as warfarin, ceftriaxone, and intravenous immunoglobulin (IVIg). Larger lesions have been treated with varying degrees of success with medications such as diltiazem, bisphosphonates, probenecid, and aluminum hydroxide.
Surgical excision may be used to remove smaller lesions that are confined to a single area, especially those in painful or troubling areas of the body. Unfortunately, the nodules often grow back after surgical removal. Indeed, sometimes surgery seems to stimulate calcinosis to grow back. Having the dermatomyositis under good control may help minimize calcinosis return.
The good news is that calcinosis occasionally clears on its own with no intervention.