[Treatment of subcutaneous calcinosis in systemic disorders]

Calcinosis cutis constitutes a heterogeneous group of chronic disorder. It can be associated with disturbance of calcium and/or phosphate metabolism (metastatic, tumor calcinosis, calciphylaxis) but may also develop without any metabolic disorder, in particular during the course of connective tissue diseases. Among these, the most common are dermatomyositis and the limited form of systemic sclerosis. The physiopathology of calcinosis cutis is poorly known. It can cause pain, chronic ulcerations, infections, which are sources of sometimes major disability. Treatment of calcinosis is challenging because no drug has been shown to be reliably effective in stopping the progression or decreasing dystrophic calcifications in controlled trials. Calcium blocker and colchicine are generally prescribed as the first line systemic therapy. In the localized forms of small lesions, surgical excision is often effective and sometimes preceded by local treatments (laser therapy, extracorporeal shock wave lithotripsy, topical sodium thiosulfate, etc.) or systemic treatment (minocycline, warfarine). When calcinosis is disseminated, it may require additional treatments (aluminium hydroxyde, bisphosphonates) possibly associated with surgery in case of large lesions. Time to response may be prolonged from weeks to months. The calcinosis cutis can lead to secondary infection, pain and functional disability that have to be prevented.