From the Guidelines
Otitis externa is defined as diffuse inflammation of the external ear canal, which may also involve the pinna or tympanic membrane, characterized by rapid onset of symptoms and signs of ear canal inflammation, including tenderness of the tragus, pinna, or both, within the past 3 weeks 1.
Key Characteristics of Otitis Externa
- Diffuse inflammation of the external ear canal
- May involve the pinna or tympanic membrane
- Rapid onset of symptoms within 48 hours in the past 3 weeks
- Tenderness of the tragus, pinna, or both
- Often caused by bacterial infection, with Pseudomonas aeruginosa and Staphylococcus aureus being the most common pathogens 1
Pathophysiology
- Cellulitis of the ear canal skin and subdermis
- Acute inflammation and variable edema
- Nearly all cases in North America are bacterial, with fungal involvement being uncommon in primary otitis externa 1
Clinical Implications
- Topical antimicrobials are beneficial for treatment, while oral antibiotics have limited utility 1
- Prevention involves keeping the ears dry after swimming or bathing and avoiding insertion of objects into the ear canal 1
From the Research
Definition of Otitis Externa
Otitis externa is a common and often painful infection in the ear canal, characterized by inflammation, erythema, and swelling of the canal with variable discharge 2, 3, 4. It can be caused by bacterial or fungal invasion, with Pseudomonas aeruginosa and Staphylococcus aureus being the most common bacteria involved, and Aspergillus and Candida species being the most common fungi 2, 5, 6.
Key Features
- Inflammation of the ear canal
- Erythema and swelling of the canal
- Variable discharge
- Often caused by bacterial or fungal infection
- Pseudomonas aeruginosa and Staphylococcus aureus are the most common bacteria involved
- Aspergillus and Candida species are the most common fungi involved
Forms of Otitis Externa
- Acute otitis externa: a common condition involving inflammation of the ear canal, often caused by bacterial infection 6
- Chronic otitis externa: often caused by allergies or underlying inflammatory dermatologic conditions 3, 6
- Necrotizing otitis externa: a destructive infection of the external auditory canal, often occurring in elderly diabetic or immunosuppressed patients 3