What is calcinosis?
Calcinosis consists of cutaneous deposits of basic calcium phosphate that characteristically occur in the hands (especially over the proximal interphalangeal joints and fingertips), periarticular tissue, and over bony prominences (especially the extensor surface of the elbows and knees), but can occur virtually anywhere on the body. The deposits of calcium are firm, irregular, and generally nontender, ranging in diameter from 1 mm to several centimeters. They can become inflamed, infected, or ulcerated and may discharge a chalky white material. Calcinosis can be persistent for years. It is extremely difficult to treat, and no therapy is consistently successful. Therapies that have been used with little supporting data include warfarin (in an attempt to inhibit the vitamin K-dependent Gla matrix protein), aluminum hydroxide, diltiazem, and probenecid. Case reports of topical sodium thiosulfate have been described in patients with calcinosis cutis in the setting of systemic lupus erythematosus, dermatomyositis, and SSc, but clinical trials and even case series of significant size are lacking. Intravenous bisphosphonate use has been used with some success for calcinosis secondary to juvenile dermatomyositis, and intravenous sodium thiosulfate has been described in case reports of SSc as well (of note, thiosulfate can bind to any calcium salt, hence bone mineral density should be monitored if this medicine is used chronically for any length of time). Surgical resection should be considered a last resort option, and deposits can reoccur.