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Otitis externa (OE) or “swimmer's ear” is commonly defined as an inflammation of the external auditory canal (EAC).* Up to 10% of all persons may experience an episode of OE during their lifetime.1,2 OE most often besets children during the summer months, and can be painful and difficult to manage because of the confines of the ear canal. Early diagnosis and a stepwise treatment approach, including debridement and ototopical therapy, and on occasion systemic antimicrobials, are critical to expedient management. This chapter will review the epidemiology, pathogenesis, management, and complications of OE to facilitate an expeditious and cost-effective treatment for this common disease.
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*While strictly speaking the auricle is part of the external ear, infections of this area are less common and are dealt with below.
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The EAC is comprised of a thin lining of sebum containing epithelium over a bony and cartilaginous canal. This warm dark tunnel is a perfect culture medium for bacterial and fungal growth if the protective acidic cerumen or epithelial barrier is violated by aggressive cleaning, soapy water, skin conditions such as eczema or a heavy bacterial load.1,3
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Almost all acute otitis externa (AOE) in North America is bacterial (98%). The most common offending organisms in AOE include Staphylococcus aureus, Pseudomonas aeruginosa and other gram-negative organisms; many infections are polymicrobial organisms.1,4,5Candida spp. rarely cause primary AOE, however, they are much more prevalent in chronic OE and in partially treated AOE.1
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Conditions predisposing to AOE include recent water exposure (e.g., swimming), travel, immunocompromised states (e.g., diabetes mellitus), otologic trauma (from cotton swab use), and dermatologic conditions such as eczema. Affected patients often complain of pain limited to the ear canal which ranges from mild to severe intensity; the pain is exacerbated with auricular traction or tragal pressure. Occasionally, pain occurs with mouth opening because of the motion of the temporomandibular joint, which abuts the anterior EAC. Aural discharge may be present, and may be clear or murky colored, rarely bloody, and can be sweet or foul smelling. Fever is uncommon.
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Because of the exquisite tenderness children may exhibit with OE, physical examination may be best approached initially without instrumenting the ear canal. A magnifying, illuminating loupe or headlight, with the child lying on its contralateral side may allow for external assessment prior to instrumentation of the ear canal. The otologic examination should focus on the external ear for erythema, edema, and tenderness to palpation. Unlike children with mastoiditis in which the pinna may be protruberant, children with OE rarely have a displaced auricle. Skin surrounding the EAC and auricle may reveal cellulitis. The concha may have crusted drainage, which has collected or dried as it drips from the EAC. Many families will not clean this external part prior to a visit ...