High-dose oral vitamin D is known to enhance vitamin D receptor–mediated anti-inflammatory signaling in response to cytotoxic keratinocyte injury. Which is why this retrospective multicenter case series evaluated 33 patients with erythema from chemotherapy (85%) or acute radiation dermatitis (15%) treated with one or two oral megadoses of 100,000 IU cholecalciferol or ergocalciferol. Among 30 patients with available symptom data, 26 (87%) reported improvement within 10 days, with a median time to symptomatic improvement of 5 days. Objective erythema scores fell from a mean of 4.36 at baseline to 2.21 by day 10. The fastest responses were seen in patients with neutrophilic eccrine hidradenitis and SJS/TEN-like eruptions. No treatment-related adverse events or meaningful changes in serum calcium were observed, and 73% of patients continued anticancer therapy without interruption. | Patil, JAMA Dermatol
