Postauricular abscess: An uncommon presentation of keratosis obturans

Keratosis obturans (KO) is a rare disease involving the bony external auditory canal due to hyperkeratosis of epidermis and disturbance in the epithelial migration process resulting in deafness, otalgia, and inflammation of the ear canal skin. Complications are extremely rare. Here, we present a case of KO in an elderly female presenting as a postauricular abscess, an unreported occurrence first of its kind in the literature. A 67-year-old female patient presented with complaints of dull aching pain and decreased hearing in the left ear for 1 month and swelling behind and above the left ear for 2 weeks. On examination, there was impacted wax in the left external auditory canal and the tympanic membrane was not visualized. A high-resolution computed tomography of the temporal bone reported left otitis externa with soft-tissue density with fat strands in the left postauricular region. The patient underwent examination under microscope, followed by debridement and a subsequent cortical mastoidectomy. Histopathology confirmed the diagnosis of KO. KO is an uncommon condition caused due to occlusion of external auditory canal by desquamated keratinous plug. It is important to differentiate it with other common conditions, including necrotizing otitis externa, canal cholesteatoma, osteoradionecrosis of the external auditory meatus, and tumors of the external auditory meatus. Extracranial complications are rare, including extensive bony erosion and automastoidectomy with no intracranial complications reported till date. KO is a relatively rare condition more commonly seen in the younger age group, and postauricular abscess as a complication of KO has not been reported till date. We thus highlight the importance of awareness of such rare conditions of the external auditory canal, promoting early diagnosis, prompt treatment, and successful prevention of complications.