Data in this chapter may be updated by a Medline search using the keywords: keratitis obturans, wax keratosis, external auditory canal cholesteatoma, external auditory meatus cholesteatoma, external ear cholesteatoma, osteomyelitis of the ear, benign otitis externa, benign necrotizing otitis externa, osteonecrosis and ear canal necrosis, tympanic bone and epithelial migration of the ear. This was supplemented by obtaining all the references quoted in the papers. Sixty-six papers were considered after removing non-relevant papers and repeats. The only evidence found was in observational studies and from expert opinions.