What are the causes of xerosis (dry skin)?

From the Guidelines

Xerosis is primarily caused by a combination of environmental factors, skin care practices, and underlying medical conditions, with the most recent evidence suggesting that dry skin, excessive sweating, changes in ambient temperature or humidity, exposure to irritants or allergens, infections, and stress are key risk factors for xerosis, as noted in the 2022 Taiwan guidelines for the diagnosis and management of pediatric atopic dermatitis 1. The main causes of xerosis include:

• Environmental factors such as low humidity, cold weather, and excessive exposure to air conditioning or heating systems that remove moisture from the air
• Frequent bathing, especially with hot water and harsh soaps, which strips the skin of its natural oils, contributing to dryness
• Aging, as sebum production decreases with age, making older adults more susceptible
• Certain medical conditions like eczema, psoriasis, thyroid disorders, and diabetes, which can cause xerosis
• Medications such as diuretics, retinoids, and statins, which can lead to dry skin
• Nutritional deficiencies, particularly of essential fatty acids, vitamins A and D, which can also lead to dry skin
• Dehydration from inadequate fluid intake, which reduces overall body moisture, affecting skin hydration
• Genetic predisposition, as some people naturally have less oil-producing glands or thinner skin Understanding these causes is crucial in addressing xerosis through appropriate moisturizing routines, humidification of living spaces, gentle cleansing practices, and addressing any underlying medical conditions, as recommended in the 2022 Taiwan guidelines 1 and supported by earlier studies 1. Key recommendations for managing xerosis include:
• Avoiding dehydrating body care such as hot showers and excessive use of soaps
• Applying emollients at least once daily to the whole body
• Using soap-free shower gel and/or bath oil
• Avoiding alcoholic solutions and soaps
• Using urea- or glycerin-based moisturizer
• Considering topical steroid preparations such as prednicarbate cream for inflammatory lesions.

From the FDA Drug Label

Indications and Usage For debridement and promotion of normal healing of hyperkeratotic surface lesions, particularly where healing is retarded by local infection, necrotic tissue, fibrinous or purulent debris or eschar. Urea is useful for the treatment of hyperkeratotic conditions such as dry, rough skin, dermatitis, psoriasis, xerosis, ichthyosis, eczema, keratosis pilaris, keratosis palmaris, keratoderma, corns and calluses, as well as damaged, ingrown and devitalized nails. The causes of xerosis are not directly stated in the provided drug labels 2.

• The labels mention xerosis as a condition that can be treated with urea, but they do not provide information on its causes.
• Therefore, no conclusion can be drawn about the causes of xerosis based on the provided information.

From the Research

Causes of Xerosis

• Xerosis cutis, also known as dry skin, is a common dermatological condition that can be caused by various factors, including environmental factors such as climate and lifestyle, as well as internal factors like medication, hormone fluctuations, and organ diseases 3.
• The condition is characterized by a disrupted stratum corneum, dehydration, and impaired keratinocyte differentiation, leading to rough, scaly, and often itchy skin 4.
• Disturbed epidermal differentiation is considered the root cause of xerosis, resulting in the impairment of stratum corneum intercellular lipid bilayers and natural moisturizing factor 5.
• Xerosis can be triggered by both exogenous and endogenous factors, including cold weather, frequent showering, and certain skin diseases like atopic dermatitis 3, 5.

Factors Contributing to Xerosis

• Environmental factors like cold weather and frequent showering can contribute to xerosis by stripping the skin of its natural moisture barrier 5.
• Internal factors like medication, hormone fluctuations, and organ diseases can also play a role in the development of xerosis 3.
• Skin diseases like atopic dermatitis can increase the risk of xerosis due to the disrupted skin barrier and impaired epidermal differentiation 6.
• Lifestyle factors like harsh soaps, detergents, and excessive bathing can also contribute to xerosis by disrupting the skin's natural moisture barrier 3.

Pathophysiology of Xerosis

• Xerosis is characterized by a disrupted stratum corneum, dehydration, and impaired keratinocyte differentiation, leading to a compromised skin barrier 4.
• The skin requires a water content of 10-15% to remain supple and intact, and xerosis occurs when this water content is disrupted 3.
• The predominance of hydrophobic substances in intercellular constituents is a means of regulating the humidity of the skin, and xerosis can occur when this balance is disrupted 3.