Graded isavuconazonium sulfate challenge in a patient with hypersensitivity to fluconazole.

Hypersensitivity reactions to triazole antifungals are uncommonly reported and cross-reactivity between these agents is poorly understood. We describe our experiences in a patient who previously developed a full body rash after receiving fluconazole who was initially successfully challenged and treated with isavuconazole without experiencing any adverse effects and was later separately re-challenged and treated successfully with a full-course of isavuconazole 8 months later. She received a third course of isavuconazole approximately 10 months after her second course, and developed rash, chest tightness, dyspnea, and facial flushing.