Background
Calcinosis cutis(CC) is a rare, often insidious, chronic calcium-deposition disorder of the cutaneous tissues resulting in friability. Dystrophic CC, the most common subtype, occurs in patients with an underlying autoimmune connective-tissue disease, like scleroderma. CC is also reported post burns, wound infection, and trauma. Procedural treatments such as surgical excision, laser and extracorporeal lithotripsy have variable results with frequent recurrence or failure. Few case series providing compelling evidence for topical sodium thiosulfate(TST) as a chelating agent, to increase calcium resorption exist; however, all reported defects were small(<3cm).
Methods
A 50-year-old male with left leg linear scleroderma presented with a 2-month history of atraumatic infected left pretibial wound, after failing conservative measures. He underwent surgical debridement, with resultant histological CC diagnosis. Refractory to negative pressure wound therapy and silver-based dressings, it progressed to a 5x8cm full thickness defect. A literature review was completed to ascertain the efficacy of TST. Subsequently, TST was trialled with complete local response (soft-tissue resorption of calcium confirmed on bone scan) and he was then amenable to grafting.
Results
16 publications, reporting 48 patients with CC treated with TST were identified. Mean age was 51 years, 76% were women, the majority involved the limbs and mean duration of treatment was 4 months. 19% had complete, 60% partial and 21% had no response. One patient was allergic. Our patient was the only reported case of CC with a wound greater than 3cms.
Conclusion
Topical sodium thiosulfate may represent a safe, effective, and inexpensive non-operative adjuvant, in the management of CC.