What are some common non-inflammatory diseases of the external ear and their management options?

Non-Inflammatory Diseases of the External Ear

The most common non-inflammatory diseases of the external ear include keratosis obturans, external auditory canal cholesteatoma, benign tumors (exostoses and osteomas), and dermatologic conditions such as eczema, seborrheic dermatitis, psoriasis, and contact dermatitis—each requiring distinct management approaches ranging from conservative debridement to surgical intervention.

Keratinaceous Lesions

Keratosis Obturans

• Keratosis obturans presents with accumulation of desquamated keratin debris in the external auditory canal, causing canal widening without bony erosion 1, 2.
• The condition typically affects younger patients bilaterally and is associated with bronchiectasis and chronic sinusitis 2.
• Management consists of regular aural toilet with manual removal of keratin plugs under microscopic visualization, typically performed every 3-6 months 1, 2.
• The absence of osteonecrosis distinguishes this from external auditory canal cholesteatoma and allows for conservative management 2.

External Auditory Canal Cholesteatoma (EACC)

• EACC is characterized by focal accumulation of keratinizing squamous epithelium with underlying bony erosion and osteonecrosis, requiring more aggressive management than keratosis obturans 1, 2.
• The presence of osteonecrosis and focal overlying epithelial loss are the most reliable features distinguishing EACC from keratosis obturans 2.
• Surgical intervention is required when disease extends beyond the canal or involves significant bony erosion, using approaches similar to those for chronic ear surgery 1, 2.
• Limited disease confined to the canal can be managed with regular debridement, but progression necessitates canalplasty or more extensive procedures 1.

Benign Tumors

Exostoses and Osteomas

• Exostoses and osteomas are common benign bony growths of the external auditory canal that typically require no treatment unless they cause symptoms 3.
• Exostoses are broad-based, bilateral, multiple bony growths associated with cold water exposure, while osteomas are unilateral, pedunculated lesions 3.
• Surgical removal via canalplasty is indicated only when lesions cause recurrent otitis externa, conductive hearing loss, or complete canal obstruction 3.

Other Benign Lesions

• Benign tumors of ceruminous gland origin may present with canal obstruction or discharge and require histological examination for definitive diagnosis 4.
• All material removed from the external canal should be submitted for histological examination to exclude malignancy, particularly basal cell carcinoma, squamous cell carcinoma, or ceruminous gland tumors 4.

Dermatologic Conditions

Eczema (Atopic Dermatitis)

• Eczema presents with chronic pruritus, erythema, xerotic scaling, lichenification, and hyperpigmentation, typically starting in childhood with involvement of multiple body areas 5.
• Management includes gentle skin care, application of emollients to maintain skin barrier function, prevention of secondary bacterial infection, and use of topical corticosteroids for inflammation 5.
• Topical calcineurin inhibitors (tacrolimus 0.1% ointment or pimecrolimus 1% cream) serve as steroid-sparing alternatives for chronic management 5.

Seborrheic Dermatitis

• Seborrheic dermatitis affects the ears, scalp, and central face, presenting with greasy yellowish scaling and itching from Malassezia yeast colonization 5.
• The condition is more pronounced in patients with Down syndrome, HIV infection, and Parkinson's disease 5.
• Treatment combines topical antifungal medications to reduce yeast burden with topical anti-inflammatory agents to control inflammation and pruritus 5.

Psoriasis and Discoid Lupus Erythematosus

• Both conditions can affect the external ear with characteristic skin lesions and often involve other areas of the skin 5.
• Diagnosis requires recognition of typical lesion morphology and distribution patterns, with management following standard dermatologic protocols for each condition 5.

Contact Dermatitis

Irritant Contact Dermatitis

• Irritant contact dermatitis results from direct chemical damage by acids or alkalis, causing erythema, edema, scaling, itch, and occasional pain in a dose-dependent manner affecting all individuals 5.
• Management involves removing the irritant and applying topical corticosteroids to reduce inflammation 5.

Allergic Contact Dermatitis

• Allergic contact dermatitis occurs only in susceptible individuals with predisposition to antigens such as nickel (most common, affecting 10% of women with pierced ears), cosmetics, hearing aid materials, or topical medications 5, 6.
• Neomycin is the most common otic preparation causing sensitization, affecting 5-15% of patients with chronic external otitis, with patch testing demonstrating hypersensitivity in 13% of normal volunteers 5, 6.
• A maculopapular or eczematous eruption on the conchal bowl and ear canal, with an erythematous streak extending down the pinna where drops contact skin, indicates allergic reaction to a topical agent 5.
• Management requires discontinuing the sensitizing agent, switching to fluoroquinolone-only preparations (avoiding neomycin), and applying topical corticosteroids or calcineurin inhibitors 5, 6.

Cerumen Impaction and Wax Build-up

• Keratosis obturans, stenosis of the external meatus, and benign tumors all lead to wax accumulation causing recurrent attacks of otitis externa 4.
• Management involves regular removal through microsuction, dry mopping, or gentle irrigation with body-temperature water 4.
• Cotton buds should never be used for wax removal as they push debris deeper and can traumatize the canal 4.

Critical Diagnostic Pitfalls to Avoid

• Failing to submit all removed material for histological examination risks missing malignant tumors that can present similarly to benign conditions 4.
• Confusing keratosis obturans with external auditory canal cholesteatoma leads to inadequate treatment, as the latter requires surgical intervention when bony erosion is present 2.
• Missing contact dermatitis from hearing aids or topical medications results in persistent symptoms despite appropriate antimicrobial therapy 5, 6.
• Neglecting to distinguish between primary dermatologic conditions and secondary bacterial infection leads to inappropriate antibiotic use when topical corticosteroids are indicated 5.

When to Refer for Specialist Evaluation

• Refer to otolaryngology when bony lesions cause recurrent infections, hearing loss, or complete canal obstruction requiring surgical removal 3, 1.
• Immediate referral is warranted for suspected malignancy, progressive bony erosion from EACC, or failure to respond to conservative management 4, 1, 2.
• Dermatology consultation is appropriate for refractory dermatologic conditions requiring patch testing or systemic immunosuppressive therapy 5.