A 60-year-old man comes to the office due to problems with his right hearing aid. The patient has worn hearing aids for many years but recently got fitted for new molds because his old ones were cracked and would scratch his ear canals on insertion. Over the past 2 days, he has had drainage from the right ear that causes the aid to become clogged. His right ear canal also feels swollen, itchy, and painful. It is unclear if the patient's hearing has changed because he cannot wear his aid. He is not dizzy and does not have a sore throat, rhinorrhea, or cough. The patient has no chronic medical conditions or prior surgeries. Temperature is 37.0 C (98.6 F), blood pressure is 146/92 mm Hg, and pulse is 90/min. The right ear examination elicits moderate pain. The ear canal is swollen, is erythematous, and has purulent drainage. There is no granulation tissue, and the tympanic membrane is clear. Cranial nerve function is normal. Which of the following is the most likely diagnosis?
Otitis externa | |
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This patient with ear drainage and a swollen, painful ear canal has otitis externa (OE). OE is a skin and soft tissue infection of the external auditory canal (EAC); therefore, manifestations include pain with manipulation and EAC erythema, but the tympanic membrane (TM) is clear. OE is also called swimmer's ear due to the most common risk factor, water exposure, but other factors can lead to its development. This patient wears hearing aids, which can cause retention of moisture in the EAC. Given the cracks in his ear mold, he was also likely sustaining trauma to the EAC when inserting his hearing aids, which disrupts the skin barrier and leads to OE.
Pseudomonas aeruginosa is the most common pathogen. Topical antipseudomonal antibiotics (eg, fluoroquinolones) are first-line therapy. Patients should be instructed to keep the ear dry and avoid further trauma.
(Choice B) New hearing aid molds may raise concern for allergic contact dermatitis, a delayed-type hypersensitivity response to an allergen (eg, rubber or plastic in hearing aids). However, the physical examination would typically show a scaly appearance at all sites of contact (ie, both ears) rather than a unilateral, edematous draining ear canal.
(Choice C) Cerumen impaction is common in hearing aid users as the cerumen cannot evacuate itself normally due to EAC occlusion. It can cause ear drainage and impair hearing aid use. However, erythema, edema, and the ability to visualize the TM make cerumen impaction unlikely.
(Choice D) A cholesteatoma represents keratin-producing squamous cells trapped in the middle ear space; it can erode into surrounding structures. Although a cholesteatoma often presents as a chronically draining ear, the edematous swollen canal, presence of pain, and clear TM are more suggestive of OE.
(Choice E) Necrotizing (malignant) otitis externa is a life-threatening osteomyelitis of the skull base that occurs in elderly patients with diabetes mellitus. It can present with ear drainage but would also cause severe ear pain and, characteristically, granulation tissue on the floor of the EAC.
(Choice F) Serous otitis media with effusion could cause a draining ear in the presence of a TM perforation. However, this patient's TM was clear with no perforation and there was EAC inflammation.
Educational objective:
Otitis externa is characterized by pain, erythema, edema, and discharge. Loss of cerumen, trauma, and foreign materials in the ear canal increase the risk. The most common pathogen is Pseudomonas aeruginosa.