external otitis generally resolves in a few days with topical washes and antibiotics, complete return of hearing and cerumen gland function may take a few more days. once healed completely, the ear canal is again self-cleaning. until it recovers fully, it may be more prone to repeat infection from further physical or chemical insult. effective medications include ear drops containing antibiotics to fight infection, and corticosteroids to reduce itching and inflammation. in painful cases, a topical solution of antibiotics such as aminoglycoside, polymyxin or fluoroquinolone is usually prescribed. antifungal solutions are used in the case of fungal infections. external otitis is almost always predominantly bacterial or predominantly fungal so that only one type of medication is necessary and indicated. cleaning removal of debris (wax, shed skin, and pus) from the ear canal promotes direct contact of the prescribed medication with the infected skin and shortens recovery time. when canal swelling has progressed to the point where the ear canal is blocked, ear drops may not penetrate far enough into the ear canal to be effective. the physician may need to carefully insert a wick of cotton or other commercially available, pre-fashioned, absorbent material called an ear wick and then saturate that with the medication. the wick is kept saturated with medication until the canal opens enough that the drops will penetrate the canal without it. removal of the wick does not require a health professional. antibiotic ear drops should be dosed in a quantity that allows coating of most of the ear canal and used for no more than 4 to 7 days. the ear should be left open. it is imperative that visualization of an intact tympanic membrane (eardrum) is noted. use of certain medications with a ruptured tympanic membrane can cause tinnitus, vertigo, dizziness and hearing loss in some cases. prognosis otitis externa responds well to treatment, but complications may occur if it is not treated. individuals with underlying diabetes, disorders of the immune system, or history of radiation therapy to the base of the skull are more likely to develop complications, including malignant otitis externa. in these individuals, rapid examination by an otolaryngologist (ear, nose, and throat physician) is very important. chronic otitis externa spread of infection to other areas of the body necrotizing external otitis otitis externa haemorhagica necrotizing external otitis necrotizing external otitis (malignant otitis externa) is an uncommon form of external otitis that occurs mainly in elderly diabetics, being somewhat more likely and more severe when the diabetes is poorly controlled. even less commonly, it can develop due to a severely compromised immune system. beginning as infection of the external ear canal, there is an extension of the infection into the bony ear canal and the soft tissues deep to the bony canal. unrecognized and untreated, it may result in death. the hallmark of malignant otitis externa (moe) is unrelenting pain that interferes with sleep and persists even after swelling of the external ear canal may have resolved with topical antibiotic treatment. it can also cause skull base osteomyelitis (sbo), manifested by multiple cranial nerve palsies, described below under the "treatment" heading. natural history moe follows a much more chronic and indolent course than ordinary acute otitis externa. there may be granulation involving the floor of the external ear canal, most often at the bony-cartilaginous junction. paradoxically, the physical findings of moe, at least in its early stages, are often much less dramatic than those of ordinary acute otitis externa. in later stages, there can be soft tissue swelling around the ear, even in the absence of significant canal swelling. while fever and leukocytosis might be expected in response to bacterial infection invading the skull region, moe does not cause fever or elevation of white blood count. treatment of moe unlike ordinary otitis externa, moe requires oral or intravenous antibiotics for cure. pseudomonas is the most common offending pathogen. diabetes control is also an essential part of treatment. when moe goes unrecognized and untreated, the infection continues to smolder and over weeks or months can spread deeper into the head and involve the bones of the skull base, constituting skull base osteomyelitis (sbo). multiple cranial nerve palsies can result, including the facial nerve (causing facial palsy), the recurrent laryngeal nerve (causing vocal cord paralysis), and the cochlear nerve (causing deafness). the infecting organism is almost always pseudomonas aeruginosa, but it can instead be fungal (aspergillus or mucor). moe and sbo are not amenable to surgery, but exploratory surgery may facilitate the culture of unusual organism(s) that are not responding to empirically used anti-pseudomonal antibiotics (ciprofloxacin being the drug of choice). the usual surgical finding is diffuse cellulitis without localized abscess formation. sbo can extend into the petrous apex of the temporal bone or more inferiorly into the opposite side of the skull base. the use of hyperbaric oxygen therapy as an adjunct to antibiotic therapy remains controversial. complications as the skull base is progressively involved, the adjacent exiting cranial nerves and their branches, especially the facial nerve and the vagus nerve, may be affected, resulting in facial paralysis and hoarseness, respectively. if both of the recurrent laryngeal nerves are paralyzed, shortness of breath may develop and necessitate tracheotomy. profound deafness can occur, usually later in the disease course due to relative resistance of the inner ear structures. gallium scans are sometimes used to document the extent of the infection but are not essential to disease management. skull base osteomyelitis is a chronic disease that can require months of iv antibiotic treatment, tends to recur, and has a significant mortality rate. epidemiology the incidence of otitis externa is high. in the netherlands, it has been estimated at 12–14 per 1000 population per year, and has been shown to affect more than 1% of a sample of the population in the united kingdom over a 12-month period. history during the tektite project in 1969 there was a great deal of otitis externa. the diving medical officer devised a prophylaxis that came to be known as, "tektite solution", equal parts of 15% tannic acid, 15% acetic acid and 50% isopropyl alcohol or ethanol. during tektite ethanol was used because it was available in the lab for pickling specimens.