Deafness | Hearing loss | classification and causes

External Otitis/swimmer’s ear

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External Otitis/swimmer’s ear

Otitis externa is a condition that causes inflammation (redness and swelling) of the external ear canal, which is the tube between the outer ear and eardrum.

Otitis externa is often referred to as “swimmer’s ear” because repeated exposure to water can make the ear canal more vulnerable to inflammation.

External otitis is usually caused by gram-negative rods (eg, Pseudomonas, Proteus) or fungi (eg, Aspergillus), which grow in the presence of excessive moisture. In diabetic or immunocompromised patients, persistent external otitis may evolve into osteomyelitis of the skull base (so-called, malignant external otitis). Usually caused by Pseudomonas aeruginosa, osteomyelitis begins in the floor of the ear canal and may extend into the middle fossa floor, the clivus, and even the contralateral skull base.

Symptoms and Signs of Acute External Otitis

Patients with external otitis have pain and drainage. Sometimes, a foul-smelling discharge and hearing loss occur if the canal becomes swollen or filled with purulent debris. Exquisite tenderness accompanies traction of the pinna or pressure over the tragus. Otoscopic examination is painful and difficult to conduct. It shows the ear canal to be red, swollen, and littered with moist, purulent debris and desquamated epithelium.

Otomycosisis more pruritic than painful, and patients also complain of aural fullness. Otomycosis caused by A. niger usually manifests with grayish black or yellow dots (fungal conidiophores) surrounded by a cottonlike material (fungal hyphae). Infection caused by C. albicans does not show any visible fungi but usually contains a thickened, creamy white exudate, which can be accompanied by spores that have a velvety appearance.

Furuncles cause severe pain and may drain sanguineous, purulent material. They appear as a focal, erythematous swelling (pimple).

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Treatment

Treatment of external otitis involves protection of the ear from additional moisture and avoidance of further mechanical injury by scratching. In cases of moisture in the ear (eg, swimmer’s ear), acidification with a drying agent (ie, a 50/50 mixture of isopropyl alcohol/white vinegar) is often helpful. When infected, an otic antibiotic solution or suspension of an aminoglycoside (eg, neomycin/polymyxin B) or fluoroquinolone (eg, ciprofloxacin), with or without a corticosteroid (eg, hydrocortisone), is usually effective.

Purulent debris filling the ear canal should be gently removed to permit entry of the topical medication. Drops should be used abundantly (five or more drops three or four times a day) to penetrate the depths of the canal. When substantial edema of the canal wall prevents entry of drops into the ear canal, a wick is placed to facilitate their entry. In recalcitrant cases— particularly when cellulitis of the periauricular tissue has developed—oral fluoroquinolones (eg, ciprofloxacin, 500 mg twice daily for 1 week) are used because of their effectiveness against Pseudomonas. Any case of persistent otitis externa in an immunocompromised or diabetic individual must be referred for specialty evaluation.

Treatment of “malignant external otitis” requires prolonged antipseudomonal antibiotic administration, often for several months. Although intravenous therapy is often required initially (eg, ciprofloxacin 200–400 mg every 12 hours), selected patients may be graduated to oral ciprofloxacin (500–1000 mg twice daily). To avoid relapse, antibiotic therapy should be continued, even in the asymptomatic patient, until gallium scanning indicates marked reduction or resolution of the inflammation. Surgical debridement of infected bone is reserved for cases of deterioration despite medical therapy.

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