Otitis Externa

Inflammation of the external auditory canal, bacterial (Pseudomonas aeruginosa, Staph aureus most common), fungal/otomycosis (Aspergillus, Candida), or eczematous/allergic.

Classified: acute diffuse ("swimmers ear"), acute localized (furuncle), chronic (>3 months), necrotizing/malignant (invasive, skull base extension; primarily diabetics/immunocompromised).

Ear pain (often severe, disproportionate to findings), itching, discharge, reduced hearing if canal occluded, tenderness on tragal pressure/pinna movement (distinguishes from otitis media).

Otoscopy: canal erythema/edema/debris. Risk factors: swimming, humid climate, cotton bud use, hearing aid/earplug use, eczema, diabetes.

Malignant otitis externa red flags: severe unremitting pain (worse at night), granulation tissue at bony-cartilaginous junction, cranial nerve palsies, diabetic/immunocompromised, treatment failure ; can progress to skull base osteomyelitis.

Clinical (otoscopy). Ear swab if severe/recurrent/refractory.

Diabetes screening if recurrent/severe. CT/MRI + ESR/CRP if malignant otitis externa suspected.

Differentials: otitis media with perforation, furunculosis, contact dermatitis of canal, cholesteatoma, foreign body, malignant otitis externa.

• Aural toilet: clinician cleaning/suction if tolerated

• Topical treatment (first-line): combination antibiotic-steroid drops (ciprofloxacin-dexamethasone; avoid neomycin if perforation possible; ototoxicity) qds-tds × 7 days; acetic acid drops for mild disease/prophylaxis

• Ear wick: if canal too swollen for drop penetration

• Fungal: topical antifungal (clotrimazole solution) + thorough aural toilet

• Analgesia: NSAIDs/paracetamol

• Avoid water exposure/cotton buds during treatment

• Oral antibiotics: not routine; reserve for spreading cellulitis, immunocompromised, or topical failure

• Malignant otitis externa (EMERGENCY): admission, IV antipseudomonal antibiotics (prolonged course, weeks), urgent ENT, imaging, optimize glycemic control

Prevention: keep ears dry, avoid cotton buds, acidifying prophylactic drops after swimming if recurrent.

Referral: ENT for recurrent/chronic disease, treatment failure, suspected malignant otitis externa (emergency).