Chronic Otitis Externa can present similar to AOE, is not only long standing, but the inflammation is usually secondary to eczema, psoriasis, seborrheic dermatitis, or fungi (Candida albicans and Aspergillus). Rarely fungi only, can cause AOE. Wax in the ear can combine with the swelling of the canal skin and any associated pus to block the canal and decreases hearing. In more severe or untreated cases, the infection can spread to the surrounding soft tissues causing Malignant or Necrotic Otitis Externa. These are more likely in diabetics, immune suppression, and in the elderly. In its mildest forms, EOE is so common that some physicians have suggested that most people will have at least a brief episode at some point in life. A small percentage of people have an innate tendency toward chronic external otitis. These folks have a genetic predisposition for producing too small amount of or an inferior (too little IgA) protective wax.
Most people can avoid AOE altogether once they understand the intricate mechanisms of the disease. The skin of the bony ear canal is unique, in that it is not movable but is closely attached to the bone, and it is almost paper-thin. For these reasons it is easily abraded or torn by even minimal physical force. Inflammation of the ear canal skin typically begins with a physical insult, most often from injury caused by attempts at self-cleaning or scratching with cotton swabs, pen caps, finger nails, hair pins, keys, or other small implements. This trauma and prolonged water exposure in the forms of swimming, bathing, showering or exposure to extreme humidity, which can compromise the protective barrier function of the canal skin, allowing bacteria to flourish. Densely impacted wax, usually caused by enthusiastic use of cotton swabs, can put enough pressure on the ear canal skin to injure it and initiate infection. A sensation of blockage or itching can prompt attempts to clean, scratch, or open the ear canal, which potentially worsens and perpetuates the condition. The cotton fibers of a swab are abrasive to the thin, fixed canal skin. Self-manipulative measures to improve the condition often make it worse and are to be discouraged, in that it can result in significant injury to the ear. It is well established that the ear canal is self-cleaning. The top layer of the ear canal skin normally migrates toward the ear opening, essentially sweeping the canal on a continuing basis. In other words, a normal ear canal is self-cleaning.
Pain is the predominant complaint and the only symptom and is directly related to the severity of AOE. Unlike Otitis Media, the pain of AOE is worsened if the ear is pulled gently. Patients may also experience ear discharge and itchiness. Initially, when doctors look inside the ear with an otoscope, they observe very little abnormality. If they are astute, they may notice a decrease of the normal ear wax. However, when enough swelling and discharge in the ear canal is present to block the opening, the eardrum cannot be seen. Looking at the eardrum is very important to the doctor in that this is how the diagnosis of Otitis Media is made and to rule out a punctured ear drum. The “pus” exuding from the canal is not true pus (all white cells), but the liquid debris of wax, dead skin, and the previous drops placed within the canal for treatment.
The treatment when EOA is very mild is simply to refrain from swimming or washing ones hair for a few days, and keeping all implements out of the ear. It is a self-limiting, self-resolving condition! However, if the infection is moderate to severe, or if the climate is humid enough that the skin of the ear remains moist, spontaneous improvement may not occur.
Effective therapy for the ear canal includes acidifying and drying agents, used either singly or in combination. When severe, topical solutions (or suspensions) of eardrops are the mainstays of treatment for EOA. Effective medications include eardrops containing antibiotics to fight infection, and corticosteroids to reduce itching and inflammation. Some contain antibiotics, either antibacterial or antifungal, and others are simply designed to mildly acidify the ear canal environment to discourage bacterial growth. Some prescription drops also contain anti-inflammatory steroids, which help to resolve swelling and itching. Cortisporin (neomycin-polymyxin B-hydrocortisone), Ciprodex ear drops ( Ciprofloxacin and dexamethasone), Gentisone HC ear drops (Gentamicin and hydrocortisone), Ciproxin HC ear drops ( ciprofloxacin and hydrocortisone), Sofradex ear drops (containing Framycetin Sulphate, Gramicidin, Dexamethasone/sodium metasulphobenzoate, Phenylethanol), Kenacomb ear drops, ( triamcinolone acetonide, neomycin and gramicidin (antibiotics) and nystatin (antifungal).
Over the counter ear drops are also available, including spirit drops (alcohol solution) which dries out the ear, and drops such as Aqua Ear which contains a mixture of alcohol and acetic acid, to dry the ear and make it difficult for microbes to grow. Home remedies with half Vodka or Gin with half vinegar can also be used in a pinch. Athletes Foot OTC preparations such as a topical antifungal like 1% clotrimazole are also effective. 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, topical drops may not penetrate far enough into the ear canal to be effective. Inserting cotton (earwick) saturated with medication is frequently applied. The wick is kept saturated with medication until the canal opens sufficiently then the drops will penetrate. If the canal is significantly edematous, a foam (Pope) can be used. Antibiotic eardrops should be given for 7 days. The ear should be left open. Although the AOE generally resolves in a few days with topical washes and antibiotics, complete return of hearing and cerumen gland function may take a few weeks. Once healed completely, the ear canal is again self-cleaning. Until it recovers fully, the canal may be more prone to repeat infection from further physical or chemical insult.
Preventing acute external otitis are similar to those for treatment. Avoid inserting anything into the ear canal. (Q-tips or cotton swabs is the most common event leading to AOE.) Other measures to use after prolonged swimming in a person prone to external otitis is to dry the ear canals with a hair dryer. Alternatively, drops containing dilute acetic acid and alcohol(2:1) will do the job. Avoid swimming in polluted water. Do not wash hair or swim if very mild symptoms of AOE begin. The use of earplugs or bathing caps when swimming and earplugs while shampooing hair may help prevent EOA. Hard and poorly fitting earplugs can scratch the ear canal skin and set off an episode. A simple method of making a soft waterproof disposable earplug is with cotton balls covered with Vasoline. These coated cotton balls are NOT inserted into the ear canal, but pressed into the ear to cover the opening of the canal.