Case of Epidermolytic Ichthyosis with a Novel L157P Mutation in KRT10 Complicated by Hypercalcemia

A 23-year-old man with epidermolytic ichthyosis (EI) and a novel L157P mutation in the KRT10 gene presented with erythroderma, bullae, and hyperkeratosis, complicated by hypercalcemia. He had been treated with etretinate and topical maxacalcitol, which likely contributed to his hypercalcemia. Laboratory tests confirmed elevated calcium levels and other markers indicative of vitamin D intoxication. The hypercalcemia improved with hydration and discontinuation of maxacalcitol, which was replaced with tacalcitol. Genetic analysis revealed the L157P mutation in KRT10, not found in his family or 100 healthy volunteers. This case highlighted the risk of hypercalcemia with combined oral retinoid and topical vitamin D3 treatments, especially in patients with renal impairment.