Systemic Sodium Thiosulfate as an Adjunct Treatment in Calcinosis: A Retrospective Study.

(1) Background: Calcinosis of the skin mainly appears in connective tissue disorders (dystrophic subtype). It may cause inflammation, ulceration, pain, and restricted joint mobility. Management is difficult; sodium thiosulfate is one potential therapeutic agent with promising data on intralesional and topical formulation for smaller calcified lesions. There are very limited data on systemic administration. (2) Methods: A retrospective study was conducted at our department to assess the efficacy of oral and intravenous sodium thiosulfate in dystrophic calcinosis between 2003 and 2023. (3) Results: Seven patients were identified, who received systemic sodium thiosulfate (intravenous or oral). The mean duration of calcinosis at the time of administration was 3.8 ± 4 years (range 0-11). Intravenous sodium thiosulfate was administered in doses of 12.5-25 g two or three times during one week of the month for 4.5 ± 3.9 months on average. Orally, 1-8 g was administered daily for 29.1 ± 40.9 months on average. Four of seven patients had a partial response (57.1%). Despite no complete response, pain, ulceration and inflammation frequency decreased, and sodium thiosulfate prevented further progression in responsive patients. (4) Conclusions: Based on our experience and literature data, systemic sodium thiosulfate may be a potential adjunct therapy in calcinosis, especially if inflamed or ulcerating.