Otitis Externa Overview and Classification

Otitis Externa

• An inflammation or infection of the external auditory canal (EAC), the auricle, or both.
• Can be found in all age groups.

Otitis Externa Classification

• Acute Diffuse OE: Most common form, typically seen in swimmers
• Acute Localized OE: Associated with infection of a hair follicle.
• Chronic OE: Same as acute diffuse OE but of longer duration (>6 weeks).
• Otomycosis: Infection of the ear canal from a fungal species.
• Eczematous OE: Encompasses various dermatologic conditions such as atopic dermatitis, psoriasis, systemic lupus erythematosus, and eczema.
• Necrotizing (malignant) OE: Infection that extends into the deeper tissues adjacent to the EAC; occurs primarily in immunocompromised adults (e.g., diabetics, patients with AIDS).

Pathophysiology

• Moisture retention: Trapped moisture in the EAC can macerate the skin and create a breeding ground for bacteria.
• Obstruction: Excessive cerumen, debris, surfer's exostosis, or a narrow and tortuous canal can lead to infection by means of moisture retention.
• Absence of cerumen: Repeated water exposure or overcleaning can lead to infection.
• Trauma: Can alter the ear canal pH and lead to infection.
• Inflammatory Response: Inflammation, edema, exudate, and pus can occur in the EAC. Infection can spread to cause cellulitis of the face or neck.

Presenting Symptoms

• Otalgia: Pain, ranging from mild to severe, typically progressing over 1-2 days.
• Discharge: Initially clear, quickly becomes purulent and foul-smelling.
• Hearing loss
• Ear fullness or pressure
• Erythema, edema, and narrowing of the EAC
• Tinnitus
• Fever
• Itching: Especially in fungal OE or chronic OE
• Severe Deep Pain: Immunocompromised patients may have necrotizing OE.
• Cellulitis of the face or neck or lymphadenopathy of the ipsilateral neck
• Bilateral symptoms: Rare
• History of exposure to or activities in water: Frequent (e.g., swimming, surfing, kayaking)
• History of preceding ear trauma: Usually (e.g., forceful ear cleaning, use of cotton swabs, or water in the ear canal)

Physical Exam

• Pain upon palpation of the tragus or application of traction to the pinna: Hallmark of OE.
• Erythema, edema, and narrowing of the external auditory canal
• Purulent or serous discharge
• Conductive hearing loss
• Cellulitis of the face or neck or lymphadenopathy of the ipsilateral neck: Can occur in some patients.

Differential Diagnosis

• Ear canal trauma
• Ear canal carcinoma
• Otitis media with a perforation
• Preauricular cyst and fistula
• Chondritis
• Lacerations
• Cranial nerve palsy
• Atopic dermatitis
• Cerumen impaction
• Foreign body
• Herpes Zoster Oticus
• Intracranial abscess
• Skull base osteomyelitis
• Furuncle
• Hearing loss
• Wisdom tooth eruption

Treatment

• Pain management
• Debris removal from the canal
• Topical medications: Control edema and infection. Ciprofloxacin-Hydrocortisone and Neomycin-polymyxin B-hydrocortisone are first-line agents.
• Avoidance of contributing factors:
• Prescribe an initial seven-day course of topical medication: Continue for an additional week if symptoms have not resolved.
• Reevaluation for treatment failure: If symptoms persist after one to two weeks.

Geriatric Population

• Necrotizing External Otitis: Typically occurs in older adults with diabetes mellitus or immunocompromise.
• Infection and damage to the bones of the ear canal and at the base of the skull: Hallmark sign is granulation tissue in the deep meatus at the bony cartilaginous junction.

Explore the various forms and classifications of otitis externa, a common ear condition affecting individuals across all ages. This quiz delves into the specifics of acute and chronic types, along with their pathophysiology. Test your understanding of this important medical topic.