What Is Considered 'Dry Skin,' Exactly?
Dry skin (xerosis) is a clinical condition characterized by rough, scaly, pruritic skin with reduced water content below the 10-15% threshold needed to maintain suppleness and intact barrier function. 1, 2
Clinical Definition and Pathophysiology
Xerosis represents a dysfunction of the epidermal barrier resulting from disrupted stratum corneum, dehydration, and impaired keratinocyte differentiation. 3 The condition manifests when the skin's water content falls below the critical 10-15% level required for normal suppleness and integrity. 2
The underlying pathophysiology involves:
- Disturbed epidermal differentiation leading to impaired stratum corneum intercellular lipid bilayers and reduced natural moisturizing factor 1
- Disrupted corneocyte and lipid-enriched intercellular bilayer structure 1
- Compromised barrier function with increased transepidermal water loss 3
Clinical Presentation
Dry skin presents with characteristic features that distinguish it from normal skin:
- Rough, scaly texture with visible flaking or desquamation 3, 4
- Pruritus (itching) that may lead to excoriations and secondary infection risk 5, 4
- Cracked and fissured appearance in more severe cases 4
- Potential progression to eczema craquelé, dyshidrotic eczema, or asteatotic eczema if untreated 4
Special Considerations in Older Adults
In elderly patients (over 65 years), xerosis is commonly associated with pruritus (Willan's itch) but is NOT a normal part of aging—it is a treatable condition. 6, 5 The British Association of Dermatologists specifically defines pruritus in the elderly as chronic itching occurring in those aged over 65 years, commonly associated with xerosis. 6
Contributing factors in older adults include:
- Intrinsic changes in keratinization and lipid content 5
- Medication effects (particularly diuretics) 5
- Environmental factors (overuse of heaters or air conditioners) 5
- Multifactorial etiology requiring comprehensive assessment 5
Context in Underlying Skin Conditions
Xerosis is a common symptom in chronic inflammatory dermatoses, particularly atopic dermatitis (eczema), where it reflects the underlying barrier dysfunction. 1, 3 In patients with eczema or psoriasis history:
- General dry skin in the past year is one of the diagnostic criteria for atopic dermatitis 7
- Xerotic skin may develop inflammatory complications including eczema and fissures 6
- The condition requires more aggressive barrier restoration than isolated xerosis 8
Distinguishing Dry Skin from Other Conditions
When evaluating dry skin complaints, systematically determine whether it is an isolated complaint or part of an underlying dermatological condition, as this fundamentally changes management. 8 Key distinguishing features include:
- Isolated xerosis: dry, scaly skin without inflammation or specific distribution pattern 8
- Atopic dermatitis: requires itchy skin condition plus three or more criteria including history of skin crease involvement, atopic family history, general dry skin in past year, visible flexural eczema, and early childhood onset 7
- Contact dermatitis: symptoms worsen with specific exposures to irritants or allergens 9, 8
Common Pitfall
Do not dismiss xerosis as merely cosmetic—it causes discomfort, pruritus, negative quality of life impact, and creates risk for secondary complications including infection. 1, 5, 4 The condition requires active treatment with barrier restoration strategies rather than simple reassurance.