Otitis externa is an acute or chronic inflammation of the external auditory canal, commonly caused by bacterial or fungal infections. Also referred to as swimmer’s ear, this condition arises due to moisture retention, minor trauma, or underlying dermatologic disorders. It typically affects individuals exposed to water, humid environments, or frequent ear instrumentation.
Etiology: Common Causes
Bacterial Infections
The most prevalent cause of otitis externa is bacterial infection, with the primary pathogens being:
- Pseudomonas aeruginosa
- Staphylococcus aureus
Fungal Infections (Otomycosis)
Fungal otitis externa accounts for a smaller subset and is often secondary to prolonged antibiotic use.
- Aspergillus species
- Candida albicans
Non-Infectious Factors
- Excessive moisture: Retained water creates a breeding ground for pathogens
- Trauma: Frequent use of cotton swabs or hearing aids can cause microabrasions
- Dermatologic conditions: Eczema, psoriasis, or seborrheic dermatitis can predispose to inflammation
- Allergic reactions: Topical medications or ear plugs may trigger hypersensitivity
Pathophysiology
Otitis externa begins when the skin of the ear canal loses its natural protective barrier. Moisture and minor trauma facilitate microbial entry and colonization. As the infection progresses, inflammation leads to pain, swelling, and exudate formation, potentially causing canal obstruction.
Clinical Presentation: Recognizing Otitis Externa Symptoms
Hallmark Symptoms
- Otalgia (ear pain): Sharp, throbbing, often worsened by manipulation of the pinna or tragus
- Pruritus: Early itching sensation, particularly in fungal infections
- Otorrhea: Purulent or serous discharge from the external auditory canal
- Fullness or hearing loss: Due to canal edema or debris
- Erythema and edema: Inflammation visible at the ear canal entrance
Advanced or Complicated Cases
- Periauricular cellulitis
- Tender cervical lymphadenopathy
- Fever and systemic signs in severe infections
Classification of Otitis Externa
| Type | Characteristics |
|---|---|
| Acute diffuse | Most common; bacterial; sudden onset |
| Chronic | Lasting >3 months; associated with eczema |
| Furunculosis | Localized infection of hair follicle |
| Necrotizing (Malignant) | Life-threatening; affects diabetics/immunocompromised |
| Otomycosis | Fungal; pruritus, white/black spores visible |
Diagnostic Approach to Otitis Externa
Clinical Evaluation
- History taking: Recent swimming, ear manipulation, or dermatologic issues
- Physical examination: Otoscopic findings include:
- Canal erythema, edema
- Discharge or debris
- Pain with tragus or auricle movement
Additional Investigations (If Needed)
- Culture and sensitivity: For refractory or recurrent cases
- CT or MRI: In suspected necrotizing otitis externa to assess bone involvement
- Blood tests: Evaluate glucose levels in diabetic patients
Treatments: Comprehensive Medical Management
Initial Management
- Aural toilet: Careful cleaning and suction of debris by a clinician
- Avoid moisture: Keep the ear dry, avoid swimming or water exposure
Topical Therapy (First-line)
- Antibiotic drops:
- Ciprofloxacin
- Neomycin/polymyxin B/hydrocortisone
- Steroid drops:
- Reduces inflammation and itching
Antifungal Treatment
- Clotrimazole or Acetic acid ear drops for otomycosis
- Debridement may be necessary for effective antifungal penetration
Analgesia
- NSAIDs or acetaminophen to manage pain
- Severe cases may require prescription analgesics
Systemic Antibiotics
- Reserved for:
- Immunocompromised patients
- Extension beyond the ear canal
- Necrotizing otitis externa
Necrotizing Otitis Externa: A Medical Emergency
Risk Factors
- Elderly diabetic patients
- Immunocompromised individuals (e.g., cancer, HIV)
Clinical Features
- Severe unrelenting pain
- Cranial nerve involvement (VII, IX, X)
- Granulation tissue in the canal
- Facial palsy
Management
- Hospital admission
- IV antibiotics (ciprofloxacin or ceftazidime)
- Imaging monitoring
- Long treatment duration (6–8 weeks minimum)
Prevention
Proactive Measures
- Dry ears thoroughly after swimming or bathing
- Avoid inserting objects into the ear canal
- Use earplugs when swimming in untreated water
- Apply acidifying drops (e.g., acetic acid) in at-risk individuals
Patient Education
- Counsel against cotton swab use
- Maintain good ear hygiene
- Manage chronic skin conditions effectively
Prognosis and Follow-Up
Typical Course
- Acute otitis externa usually resolves within 7–10 days with appropriate therapy
- Chronic or fungal cases may require prolonged treatment and follow-up
Red Flags
- Persistent symptoms beyond 3 weeks
- Recurrent infections
- Signs of necrotizing spread or cranial nerve involvement
Regular follow-up is essential in high-risk populations to ensure resolution and prevent complications.
Frequently Asked Questions:
Is otitis externa contagious?
No, otitis externa is not typically contagious. It results from local factors within the ear canal.
Can it heal without treatment?
Mild cases may resolve with ear dryness alone, but most benefit from topical medication.
What is the difference between otitis externa and otitis media?
Otitis externa affects the outer ear canal, while otitis media involves the middle ear behind the eardrum.
How can I relieve the pain at home?
Use warm compresses and over-the-counter pain relievers. Avoid moisture and manipulation of the ear.
When should I see a doctor?
If symptoms persist beyond a few days, worsen, or if you have underlying conditions like diabetes or immune suppression.
Otitis externa is a common, often preventable condition with a high rate of recovery when diagnosed early and treated properly. Understanding the etiological factors, recognizing key symptoms, and applying targeted treatment protocols are vital to preventing complications and ensuring patient comfort. A comprehensive, individualized approach remains essential, particularly in vulnerable populations.
