Although Toynbee was frequently credited for noting a pearly white shining mass occupying the posterior surface of the external canal which he called molluscum contagiosum in 1850, keratosis obturans was in fact first properly described and named by Wreden of St. Petersburg in 1874, who differentiated the condition from that of impacted wax (which was then called ceruminosis obturans). Schofield further added another terminology, cholesteatoma of the external auditory canal in 1893, which he attributed to an insect sting or bite.
Piepergedes and Behnke clarified the two conditions defining the distinction between the two, which until then had been considered different presentations of the same disease; keratosis obturans was defined as an accumulation of keratin plugs within the ear canal which may result in some widening of the external auditory canal, and external auditory canal cholesteatoma as bone erosion resulting from squamous tissue at a specific site in the external auditory canal. Further distinction has been drawn between the two conditions on the grounds of differing clinical and pathologic features.
Inflammatory KM:Acute infection, such as viral infection, through which the epithelial migration can be transiently changed by the inflammatory process.
- Removal of keratin can cure the inflammatory type.
Silent LM:Caused by abnormal separation of keratin
- Continuous progression of the disease, even after first removal; thus, continuous regular aural toileting is required to treat the disease
- Seborrhoeic dermatitis
- Sinusitis or bronchiectasis (77% of juvenile and 20% of adult cases)
KO typically manifests in a younger population and presents with an acute onset of severe ear pain with ear blockade and hearing loss.
- Severe otalgia + conductive hearing loss (due to collection of desquamated epidermal plug in ear canal)
- There is no ear discharge.
- Widening ‘ballooning’ of bony EAC
- Thickened tympanic membrane (TM ‘stands out in relief’)
ComplicationsDespite being a benign condition, left neglected, KO can result in extensive bone resorption with the involvement of vital intratemporal soft tissue structures.
- Erosion of labyrinth → Lateral semicircular canal fistula
- Erosion of dural plate
- Erosion of temporomandibular joint
- Facial nerve palsy (M/dreaded complication)
Management begins with conservative measures, however, severe pain and tightly plugged wax commonly requires general anesthesia for removal. Oftentimes, the underlying inflamed epithelium may recover with local steroid +/− antibiotic ear drops and the normal migration pattern may get restored without needing any further interventions. Some patients, however, may need long term repeated suction cleaning of the ear canal prophylactically to avoid wax impaction.