Introduction: Calciphylaxis or Calcifying Uremic Arteriolopathy (CUA) is a rare vascular disorder with a high rate of morbidity and mortality, of uncertain pathogenesis and with various risk factors involved. The diagnosis is suspected based on the findings in the clinical charts and physical examination, with a multidisciplinary approach. Intravenous Sodium Thiosulfate is a therapeutic alternative. Topical preparations based on cold cream from 10 to 25% could be considered as a treatment option in patients with contraindications/high risk of adverse effects for intravenous administration.

Objectives: To report the usefulness and efficacy of topical Sodium Thiosulfate treatment in patients with CUA.

Materials and Methods: We performed 938 kidney transplants between 1996 and 2022, and we assisted two patients with biopsy-proven CUA, and they received treatment with topical Sodium Thiosulfate. They presented a history of chronic kidney disease, hemodialysis, secondary hyperparathyroidism, treatment with vitamin D, diabetes mellitus, frequent traumatisms in the affected area, female sex and white race, all of them known risk factors.
The affected area was:
Patient 1: ulcerated lesion on left leg.
Patient 2: multiple ulcerated lesions in both lower limbs.

Results: Skin lesions resolved completely with a preparation of topical Sodium Thiosulfate based on 25% cold cream.

Conclusions: Treatment with topical preparations of Sodium Thiosulfate based on 25% cold cream was an effective therapeutic approach in both patients with contraindications/high risk of adverse effects for intravenous administration. To the best of our knowledge, only 1 case has been reported in the literature so our experience is valuable.