Case report: A 22-year-old man was referred to the Christchurch Hospital Otolaryngology service in October 2025 with six weeks of bilateral otalgia and hearing loss followed by vertigo. He had no prior ear issues or medical conditions. He was a smoker. Otoscopy revealed intact but bulging and opaque tympanic membranes. No keratin accumulation was seen. He had left beating nystagmus and bedside and video head impulse testing was consistent with right-sided vestibular failure. Audiometry revealed left-sided conductive hearing loss and right-sided complete deafness. His c-reactive protein was 46. Swabs of his ear were indicative of scanty candida which were felt to be more likely commensal growth. CT/MRI imaging showed bilateral otomastoid opacification with right-sided tegmen dehiscence and perilymphatic fistula with appearances more in keeping with infection than cholesteatoma. Treatment involved physiotherapy, bilateral ventilation tube insertion, oral steroids, antibiotic/steroid ear drops and an extended course of intravenous antibiotics as guided by the Infectious Diseases service. His otalgia and vertigo improved and his inflammatory markers normalised. His left-sided hearing returned however he had ongoing complete deafness in his right ear and he will continue to have follow-up and hearing rehabilitation. This case represents a very rare complication of acute otitis media. To our knowledge, this is the third documented case of labyrinthine fistula following acute otitis media (1, 2) and the first documented such case in an adult. Although rare, we should be aware of such potential complications as it can have significant long-term impacts. References: (1) Claes, G. et al. (2020) ‘Middle ear actinomycosis: A rare cause of acute otitis media with labyrinthine fistula’, B-ENT. (2) Jotdar, A. et al. (2025). ‘Labyrinthine fistula associated with acute otitis media: a clinical surprise’, Indian Journal of Otology.