The incidence of perilymphatic fistula as cause of sudden hearing loss is not known. We present a case with sudden unilateral hearing loss associated with a positive beta-trace protein test of an epipharyngeal fluid sample. The patient presented with sudden sensorineural hearing loss on the right side. A stapedotomy had been performed nine months previously due to otosclerosis. Intravenous therapy for the treatment of sudden hearing loss was unsuccessful. At the time of sudden hearing loss, epipharyngeal fluid was collected using a Raucocel sinus pack. Investigation using rocket immunoelectrophoresis showed the presence of beta-trace protein. Upon repeating tympanoscopy there was no obvious labyrinthine fluid egress, but the oval window was sealed with fibrin sponge and fibrin glue. The patient's hearing improved over a period of five months.