Paradoxical Response after a Voriconazole Treatment in an Immunocompetent Host with a Skull Base Osteomyelitis due to Invasive Aspergillosis

Background We describe a case of skull base osteomyelitis due to invasive aspergillosis which had been aggravated after antifungal treatment but significantly recovered by dexamethasone. Case report A 74-year-old male patient presented to neurology clinic complaining of sudden onset right-sided facial palsy and headache. Brain magnetic resonance imaging (MRI) and sphenoid sinus biopsy confirmed Aspergillus infection of skull base. He was treated with voriconazole for two months, but his headache was not relieved, and he additionally complained of vertigo and dysphagia. A subsequent MRI showed reduced enhancement of initial lesions, but increased thickness of surrounding dura mater. With an impression of paradoxical inflammatory response after antifungal treatment, parenteral dexamethasone was administered for one month while maintaining voriconazole. His symptoms improved thereafter. Conclusion A paradoxical inflammatory response during antifungal treatment in the skull base aspergillosis aggravates the neurological symptom by thickening the dura mater, which can be recovered by dexamethasone.