What causes dry patches in the ears?

What Causes Dry Patches in Ears

Dry patches in the ears are most commonly caused by inflammatory dermatoses—specifically seborrheic dermatitis, eczema (atopic dermatitis), psoriasis, and contact dermatitis—which disrupt the normal epithelial barrier and produce characteristic scaling, erythema, and pruritus. 1, 2

Primary Dermatologic Causes

Seborrheic Dermatitis

• Presents with greasy yellowish scales accompanied by itching, representing the most frequent dermatosis affecting the ear canal (56% in clinical series) 3, 4
• Secondary inflammation from Malassezia yeast colonization perpetuates the condition 3, 2
• Chronic pruritus leads to scratching, which further damages the epithelial barrier and creates a self-perpetuating inflammatory cycle 3

Eczema (Atopic Dermatitis)

• Characterized by chronic pruritus with xerotic (dry) scaling, erythema, lichenification, and hyperpigmentation 1, 2
• Typically starts in childhood with involvement of multiple body areas, though isolated ear involvement can occur 1
• The ear canal's thin epithelium is particularly vulnerable to moisture loss and barrier dysfunction 2

Psoriasis

• Affects approximately 18% of psoriasis patients at some point, presenting as well-demarcated erythematous plaques with silvery-white scale 5
• Picking and scratching exacerbate the condition through the Koebner phenomenon 5

Contact Dermatitis (Allergic and Irritant)

• Allergic contact dermatitis develops from sensitization to specific allergens, most commonly:
  • Nickel (affects ~10% of women with pierced ears) 1
  • Neomycin (causes reactions in 5-15% of patients with chronic ear conditions, with 13% of normal volunteers showing hypersensitivity) 1, 3
  • Hearing aid materials (plastics, rubber accelerators, methacrylates) affecting 27% of long-term users in one series 1, 6
  • Topical medications and their vehicle substances 1
• Irritant contact dermatitis results from mechanical friction and pressure from devices like CPAP straps, hearing aids, or earplugs, causing direct physical damage to the epidermis 7
• A maculopapular or eczematous eruption on the conchal bowl extending down the pinna where drops contact skin suggests topical agent allergy 1

Predisposing and Perpetuating Factors

Environmental and Behavioral Triggers

• Humidity or prolonged water exposure disrupts the protective epithelial barrier 1
• Trauma from aggressive wax removal, cotton swabs, or scratching permits bacterial invasion and worsens inflammation 1, 3
• Use of irritating hair products (shampoos, hair sprays, dyes) that contact the ear 1

Anatomic and Device-Related Factors

• Narrow ear canals or exostoses trap moisture and debris 1
• Hearing aids, earplugs, or earbuds create occlusion and friction 1
• Impacted cerumen obstructs the canal and retains moisture 1

Systemic Conditions

• Underlying atopic tendency predisposes to eczematous changes 1, 2
• Immunocompromised states may alter skin barrier function 3

Critical Diagnostic Distinctions

You must distinguish dermatologic dry patches from acute bacterial otitis externa, which presents with acute severe pain, purulent discharge, and intense tragal tenderness disproportionate to appearance—dermatoses typically present with chronic itching and scaling rather than acute pain 1, 3, 2

The hallmark sign of bacterial infection is tenderness when pushing the tragus or pulling the pinna, whereas dermatoses cause primarily pruritus 1

Common Pitfalls to Recognize

• Do not confuse chronic dermatitis with infection—antibiotics have limited utility in dermatitis alone unless clear bacterial superinfection develops 3, 2
• Avoid neomycin-containing products entirely when treating ear dermatoses, as neomycin is the most frequent sensitizer and worsens the condition in 5-15% of cases 1, 3, 2
• Patients often self-treat with over-the-counter preparations containing neomycin, creating iatrogenic contact dermatitis that mimics or worsens the original condition 1, 2
• Scratching and inserting objects (cotton swabs) perpetuates the inflammatory cycle—this behavior must be addressed 3, 2

When to Suspect Specific Causes

• Greasy yellowish scales with itching → seborrheic dermatitis 3, 4
• Dry xerotic scaling with lichenification → atopic dermatitis 1, 2
• Well-demarcated plaques with silvery scale → psoriasis 5
• Eruption in distribution of device contact or topical medication → contact dermatitis 1, 7
• Bilateral involvement with childhood onset → atopic dermatitis 1
• Unilateral involvement in hearing aid user → contact dermatitis to device materials 1, 6