Table 1. Etiology and corresponding treatment approaches for chronic otitis externa

Cause Pathophysiological characteristics Treatment approaches
Physical trauma(e.g., cotton swabs, earphones) Mechanical damage to the ear canal skin, causing injury to the epidermis and potential infection risk. Avoidance of physical trauma
Environmental factors(e.g., water exposure) Persistent moisture exposure from swimming or frequent bathing weakens the ear canal’s natural barrier function, promoting infection and inflammation. Drying the ear canal after exposureCessation of swimming
Bacterial infection Pathogen-induced growth and spread of pathogenic microorganisms, causing infection and inflammation. Topical or systemic antibiotics (e.g., ciprofloxacin, ofloxacin)
Fungal infections Fungal infections, especially from Aspergillus and Candida, thrive in moist environments, leading to chronic inflammation. Topical antifungals (e.g., clotrimazole 1%)
Allergic contact dermatitis Skin irritation and inflammation caused by external allergens like neomycin, shampoos, and hair sprays. Discontinuation of allergens (e.g., neomycin)Topical steroids
Chronic skin diseases(e.g., psoriasis, atopic dermatitis) Skin inflammation caused by diseases weakens skin barrier function, leading to chronic irritation. Topical corticosteroidsCoordination with dermatologyManagement of the underlying skin disease
Systemic diseases(e.g., amyloidosis, sarcoidosis, Sjögren’s syndrome) Dysregulation of immune function, contributing to systemic inflammation that affects the ear canal. Topical corticosteroidsCoordination with dermatology or rheumatology specialistsTreatment of the underlying systemic disease
Dermatophytid reaction(due to foot or nail fungal infections) A hypersensitive immune reaction (ID reaction) to fungal infections elsewhere in the body (e.g., tinea pedis, onychomycosis). Treating the primary fungal infectionAvoiding further fungal exposure
ID reaction: dermatophytid reaction.