8.3 Dry Skin

Xeroderma, xerodermia, asteatosis cutis, xerosis cutis, exsiccosis, sebostasis.

Dry skin is one of the most common dermatological diagnoses and a symptom present in many dermatological and non-dermatological diseases (prevalence ranging from 35% to 85%). No gender predilection. Affects over 50% of individuals aged  ≥65 years.

Frequent symptom in dermatoses characterized by dysfunction of the skin barrier (atopic dermatitis, psoriasis), in individuals with underlying diseases (i.e. diabetes mellitus, renal failure, hypothyroidism, etc.) or taking associated medications modifying the epidermal lipid content and barrier. 

Scaly, rough, cracked, and fissured skin surface showing loss of softness, often accompanied by pruritus, due to decreased quantity and/ or quality of lipids and/or hydrophilic substances (natural moisturizing factor) with increase of water loss.

Dry skin is caused by loss of water from the stratum corneum associated with impairment in the natural barrier function and/or lack of natural moisturizing factors (NMF).  Abnormalities in the stratum corneum (intercellular lipids), and/or impaired keratinocyte differentiation along with decreased levels of NMF (degradation products of filaggrin: lactic acid, sugars, amino acids, urea) result in dry skin secondary to transepidermal water loss and dehydration. 

Multifactorial  aetiology. Mediated by genetics, environmental factors, ageing and other factors such as ethnicity.

External Causes

• Intense skin cleansing/overwashing
• Environmental factors: cold weather, low humidity
• Occupational factors: “wet work”, contact with irritant agents

Endogenous Causes

Aging, menopause, andropause.

Skin diseases

• Inflammatory skin disorders:  atopic dermatitis, allergic contact dermatitis, irritant contact dermatitis, etc.
• Infectious skin disorders (in the chronic phase): scabies, bacterial, or fungal infections
• Genodermatoses: ichthyoses, xeroderma pigmentosum
• Neoplasms: Cutaneous T-cell lymphoma

Internal/Systemic diseases

• Endocrine or metabolic: diabetes mellitus, hypothyroidism, hyperthyroidism, primary biliary cholangitis, cholestasis, hyperparathyroidism, renal failure and hemodialysis.
• Inflammatory: Crohn's disease, ulcerative colitis
• Infections: human immunodeficiency virus (HIV), hepatitis B or C virus
• Hormonal: pregnancy, menopause
• Hematologic: myeloproliferative disorders, multiple myeloma, Hodgkin’s and Non-Hodgkin’s lymphoma, GVHD, paraneoplastic.
• Neurologic:  Autonomic neuropathy.

Psychiatric diseases

• Obsessive-compulsive disorders: excess skin washing
• Eating disorders: anorexia with nutrition deficiencies
• Addictions: alcohol or drug abuse, nicotine excess

Dietary

• Dehydration: excess perspiration, insufficient water intake
• Malnutrition

Medication-related

Drugs: Diuretics, beta-blockers, contraceptives, retinoids, long-term use of topical steroids, lipid-lowering agents (statins), radiation therapy (X-ray, UV).

Dry skin is characterized by a scaly, rough, cracked, and fissured surface and loss of softness. Skin dullness with decreased elasticity, texture coarsening and wrinkling.  Often associated with pruritus, that may lead to excoriations and hemorrhage.

Erythema may occasionally be present. Rubbing and scratching of the skin can lead to eczematous changes with a reticulate, cracked, or crazy-paving appearance (“eczema craquelé”). Recurrent and intense pruritus may lead to lichenification.

Could be  localized or  generalized .

Dry skin is more frequently present on the lower legs, dorsal forearms, sides of abdomen and hands and feet, although any area of the body may be affected. 

Dry skin can develop acutely or be a chronic condition of varying intensity (mild, moderate or severe dry skin).

Classification according to aetiopathogenesis (see above).  

Assessment of possible underlying causes: renal and liver function tests, thyroid hormone levels, vitamin levels, blood sugar, hematologic investigations. 

Measurement of transepidermal water loss (TEWL), corneometry, pH, skin roughness.

Dermatopathology
Skin biopsy can be performed in rare instances when needed to distinguish from conditions mimicking dry skin (ichthyosiform dermatoses).

Variable.  Although dry skin is often experienced in the winter, in certain individuals may be a lifelong concern.  Can be aggravated by environmental factors.

Increased risk of skin infections (via breaches in the skin surface), skin breakdown from maceration (skin folds), and from pressure in weight-bearing and pressure-prone surfaces. Chronic pruritus and scratching vicious cycle. Secondary impetiginization.

Sensitization: Allergic contact dermatitis (due to compromised skin barrier function).

Clinical diagnosis with a thorough history and physical examination.

Depending on the cause and course (see above).

Prevention: Avoidance of possible trigger factors. Treatment of co-morbidities.

Therapy: Most cases can be managed conservatively with gentle cleansing and adequate moisturization.

Use of mild cleansers: synthetic detergent cleansers or Syndet cleansers. Avoid traditional soaps. 

Skin moisturizers: Oil-based creams better than water-based lotions. Ointments are useful for preventing transepidermal water loss.  May include humectants (glycerin, urea 10 %, ammonium lactate, hyaluronic acid, gelatin), occlusives (lanolin, paraffin, petrolatum, cholesterol, stearyl alcohol) and emollients (petrolatum, dimethicone ). Application immediately after bathing or showering.

In cases with intense itch or associated dermatitis, oral antihistamines, topical corticosteroids or calcineurin inhibitors may be prescribed.

None.

Dry skin is a benign symptom that can be resolved with avoidance of triggers and incorporating adequate skincare. Some cases may persist or recur for years.    When associated with pruritus, it may lead to a considerable impairment in patients’ quality of life.