- Published on
Emergency and Acute Medicine – Otitis Externa
Otitis externa is an inflammation or infection of the auricle, external auditory canal, or the external surface of the tympanic membrane, while sparing the middle ear. It affects approximately 4 per 1,000 individuals in the United States and is commonly referred to as “swimmer’s ear” due to its frequent association with recent swimming or water exposure, although it may also occur after routine bathing. A severe form, necrotizing (malignant) otitis externa, begins in the ear canal and can extend into periauricular tissues and the skull base. This form occurs most often in elderly patients, those with diabetes, or immunocompromised individuals, is commonly caused by Pseudomonas aeruginosa, and carries a mortality rate of up to 20%.
The condition is often precipitated by trauma or abrasion of the ear canal or by maceration of the skin from prolonged moisture or excessive dryness. Predisposing factors include prior ear surgery or tympanic membrane perforation, narrow or abnormal ear canals, humidity, allergies, eczema, trauma, and abnormal cerumen production. Common pathogens include Pseudomonas aeruginosa, Staphylococcus aureus, streptococcal species, and less commonly fungal organisms.
Patients typically present with a history of recent swimming or water exposure and may report itching of the ear canal as the earliest symptom. This is often followed over one to two days by progressive ear pain, ear drainage, decreased hearing, and a sensation of ear fullness or clogging. In patients with diabetes or immunosuppression, clinicians should specifically inquire about systemic symptoms and risk factors. On examination, pain is elicited with movement of the pinna or tragus, and the external ear canal is usually swollen, erythematous, and tender, often with visible drainage or debris. Decreased auditory acuity and preauricular swelling may be present. Necrotizing otitis externa may present with severe otalgia, headache, otorrhea, periauricular swelling, and cranial nerve palsies, most commonly involving the facial nerve.
Diagnosis is primarily clinical, based on characteristic history and physical findings. Otoscopic examination typically reveals an edematous, erythematous ear canal with purulent, cheesy white, or gray-green exudate. Laboratory studies are not routinely required unless necrotizing otitis externa is suspected, in which case evaluation may include white blood cell count, erythrocyte sedimentation rate, serum glucose, and cultures. Computed tomography or magnetic resonance imaging is indicated when there are signs of systemic toxicity, suspected bony involvement, or concern for mastoiditis. Debris removal from the ear canal using gentle curettage or irrigation is both diagnostic and therapeutic, and wick placement may be necessary to ensure medication penetration in markedly edematous canals.
The differential diagnosis includes otitis media, folliculitis, foreign bodies in the ear canal, herpes zoster oticus, parotitis, mastoiditis, dental abscess, sinusitis, temporomandibular joint disorders, and cervical adenitis. In children, an ear canal foreign body should be considered when purulent drainage is present.
Management focuses on pain control, eradication of infection, and prevention of recurrence. Treatment begins with gentle cleansing of the external auditory canal to remove debris, sometimes requiring suction or curettage. A cotton or gauze wick may be placed in cases of severe canal edema. Most cases respond well to topical therapy using antiseptic, anti-inflammatory, and antibacterial ear drops. Acetic acid solutions, combination antibiotic-steroid drops, or fluoroquinolone drops such as ofloxacin are commonly used, with ofloxacin preferred when tympanic membrane perforation is suspected. Oral antibiotics are reserved for patients with facial or neck cellulitis, severe canal edema, concurrent otitis media, or immunocompromised status. Diabetic and immunocompromised patients should be treated with oral ciprofloxacin and monitored closely for progression to necrotizing otitis externa. Intravenous antibiotics and possible surgical debridement are required for necrotizing disease or severe systemic illness.
Most patients can be safely discharged with close follow-up. Admission is indicated for necrotizing otitis externa, significant pinna involvement, or signs of systemic illness. Discharge instructions should emphasize keeping the ear dry, avoiding swimming for three to four weeks, proper use of prescribed medications, and returning promptly for worsening pain, fever, hearing loss, or neurologic symptoms. Follow-up within two to three days is recommended, particularly for wick removal or if symptoms fail to improve.
Key clinical pearls include recognizing that erythema of the tympanic membrane in otitis externa may mimic otitis media, avoiding ear canal lavage until tympanic membrane integrity is confirmed, and ensuring adequate medication penetration by clearing obstructing debris. Recurrence can often be prevented through patient education focused on minimizing moisture, trauma, and irritant exposure to the external ear canal. Necrotizing otitis externa should always be suspected in diabetics or immunocompromised patients with severe ear pain, purulent otorrhea, and granulation tissue or exposed bone in the ear canal.
0 Comments
