Otitis Externa Lecture Review

Flashcards for reviewing key concepts of Otitis Externa.

Otitis Externa

Inflammation of the external auditory canal, also known as external otitis or swimmer's ear.

Common Causes Otitis Externa

Infectious, allergic, and dermatologic diseases, with acute bacterial infection being the most frequent.

Epidemiology of AOE

Affects all age groups, with approximately 10% of people developing it in their lifetime; incidence is higher in summer months.

External Auditory Canal Structure

Consists of cartilaginous and bony portions with the isthmus being the narrowest region.

Ceruminous Glands Role

Found in the cartilaginous portion of the ear canal; produce cerumen.

Fissures of Santorini

Potential role in the spread of infection from the ear canal.

Isthmus

The narrowest region of the ear canal, located at the junction of the cartilaginous and bony portions.

Pathogenesis of AOE

Breakdown of the skin-cerumen barrier, leading to inflammation, edema, pruritus, pH changes, and a favorable environment for organisms.

Common Risk Factors for AOE

Swimming, water exposure, trauma, excessive cleaning or scratching, occlusive ear devices, allergic contact dermatitis, dermatologic conditions, prior radiation therapy.

Common Bacterial Pathogens in AOE

Pseudomonas aeruginosa and Staphylococcus aureus.

Otomycosis

Fungal infections of the ear, accounting for a smaller percentage of AOE cases and often occurring after antibiotic treatment.

Common Symptoms of AOE

Ear pain, pruritus, discharge, and hearing loss.

Key Physical Examination Findings in AOE

Tenderness with tragal pressure or auricle manipulation, edematous and erythematous ear canal, presence of debris or cerumen, possible erythema of the tympanic membrane.

AOE Diagnosis

Primarily based on clinical history and physical examination; cultures reserved for severe/recurrent cases or immunocompromised patients.

Otomycosis (Differential)

Fungal infection with itching, discomfort, and discharge.

Contact Dermatitis (Differential)

Persistent edema and erythema; often with intense itching.

Cleaning the Ear Canal (AOE)

Essential first step, removal of cerumen and debris, irrigation with diluted hydrogen peroxide if TM is intact.

AOE Treatment (Intact TM, Mild)

Topical acetic acid-hydrocortisone is suggested.

AOE Treatment (Intact TM, Moderate)

Topical antibiotic with glucocorticoid (e.g., ciprofloxacin-hydrocortisone).

AOE Treatment (Nonintact TM)

Topical fluoroquinolone (e.g., ciprofloxacin-dexamethasone); avoid ototoxic preparations.

AOE Treatment (Cellulitis)

Dual therapy with topical and systemic antibiotics.

AOE Treatment (Immunocompromised)

Combined systemic and topical antibiotics are suggested.

Examples of Topical Otic Preparations

Antibiotics, antiseptics, glucocorticoids, and acidifying solutions.

AOE Pain Management

Oral NSAIDs (e.g., ibuprofen, naproxen) can be used for additional analgesia.

Counseling Points for Topical Preparations

Tilt head, pull auricle upward, fill ear canal, maintain position, protect from water, avoid swimming, disinfect devices.

AOE Prevention - Hygiene

Avoid inserting foreign objects, use earplugs for water sports, dry ear, clean hearing aids.

Malignant Otitis Externa

Requires systemic antipseudomonal antibiotics and urgent referral to otolaryngology and an infectious disease specialist.

Complications of AOE

Periauricular cellulitis and malignant otitis externa.

Necrotizing External Otitis (NEO)

Invasive infection of the external auditory canal that can lead to skull base osteomyelitis.

NEO is Typically Caused By

P. aeruginosa in more than 95 percent of cases.