Successful treatment of calcinosis cutis of fingertip in the setting of CREST syndrome with topical 20% sodium thiosulfate

Calcinosis cutis (CC) is a rare chronic process characterized by deposition of insoluble calcium salts in the skin and subcutaneous tissues. There are 5 subtypes of CC: dystrophic, metastatic, idiopathic, iatrogenic, and calciphylaxis.1 Dystrophic calcinosis is the most common type of CC and is seen in association with autoimmune connective tissue diseases such as systemic sclerosis, dermatomyositis, lupus erythematosus, and lupus panniculitis. CC is thought to occur as a result of chronic local tissue injury and is a common complication of systemic sclerosis especially the limited form (CREST syndrome: calcinosis, Reynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia), affecting approximately 25% of these patients.