Causes Of Dry Skin
Before understanding the causes of dry skin, it is important to know the structure and composition of skin:
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The natural skin barrier consists of specialized cells known as corneocytes. These corneocytes are fixed in the lipid rich layer of the skin. The disturbance in the size, number, and arrangement of corneocytes impairs the skin barrier.
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The normal skin should be able to store 10-20% of water content. The changes in water holding capacity, both too high and too low also affects the skin barrier.
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The composition of lipids in the uppermost layer is also affected by various factors like age, genetic disposition, diet (e.g., percentage of essential fatty acids) as well as drugs (e.g., cholesterol-lowering agents).
Dry skin is caused due to disturbance in this natural barrier function and/or lack of moisturizing factors in the skin. The various causes that can either alter the lipid composition or can decrease the content of moisturizing factors can be grouped as:
A. External causes
1. Skin cleansing: Excessive exposure to water can remove natural oils from the skin, making it dry. The following daily activities can cause it:
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Frequently taking long hot showers
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Excessive scrubbing of the skin
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Frequent washing of the hands
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Using harsh soaps
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Using alkaline soaps and detergents
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Excessive use of sanitizers
2. Environmental factors: Some environmental factors can also cause dry skin. These include:
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Living in cold weather where humidity is low
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Intense exposure to sunlight
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Using air conditioning system
3. Occupational factors: Some people have constant exposure to the agents that remove moisture from the skin and cause dry skin. This includes people working in hairdressings, housekeeping, catering, metal workers, construction, agriculture etc. Healthcare professionals are also at increased risk of dry skin because they have to wash their hands frequently.
B. Internal causes
These are the uncontrollable factors and include various disorders that can cause dry skin. This can be:
1. Dermatological causes
Inflammatory skin disorders: There are various skin disorders that can cause dry skin such as :
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Atopic dermatitis
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Allergic contact dermatitis
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Irritant contact dermatitis
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Seborrheic dermatitis
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Perioral dermatitis
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Dyshidrotic eczema
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Nummular eczema
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Psoriasis
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Scabies
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Skin infections
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Xeroderma pigmentosum
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Cutaneous T cell lymphoma
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Lichen planus
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Urticaria
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Drug eruptions
Genodermatoses: It refers to rare inherited skin diseases that can influence the texture, color and structure of skin depending upon the type. Common example include ichthyosis in which the skin becomes severely dry.
Infectious dermatose: These are the skin conditions that are caused by bacteria, virus, fungi, or parasites. In the chronic stage, they also cause dry skin. The disease includes pediculosis and scabies.
Neoplasms: Some forms of cancers such as cutaneous lymphoma (cancer of white blood cells) can also cause dry skin.
2. Psychiatric causes
Obsessive compulsive disorder (OCD): Some patients of OCD have the addiction of excessive cleaning and washing which can be the cause of dry skin.
Eating disorders: It includes anorexia nervosa which is characterized by self starvation that can lead to lack of essential nutrients and vitamins required to keep the skin healthy.
Alcohol addiction: The excessive consumption of alcohol causes dehydration which can eventually lead to dry skin. It can also worsen underlying skin conditions. Heavy drinking can cause alcohol use disorder (AUD) which increases the chances of several skin disorders such as dry skin, skin infections and skin cancers. According to The National Institute on Alcohol Abuse and Alcoholism, heavy drinking refers to :
3. Dietary causes
Malnutrition: Dietary causes such as deficiencies of Vitamin A, Vitamin D, zinc and iron can also cause dry skin.
Dehydration: Insufficient fluid intake and excessive perspiration can also cause dry skin.
4. Drug-related causes
Retinoids, topical corticosteroids (prolonged use), diuretics, lipid-lowering agents, calcium antagonists, beta blockers, antirheumatic drugs, contraceptives/antiandrogens, cytostatic agents, radiation dermatitis (following radiation therapy), immunomodulators can also make the skin dry.
5. Internal diseases/conditions
1. Endocrine and metabolic disorders: There are various diseases that can cause dry, cracked and flaky skin. These disorders include:
- Chronic kidney disease
- Diabetes mellitus
- Liver disorders (primary biliary cholangitis, primary sclerotic cholangitis, drug-induced cholestasis, extrahepatic cholestasis)
- Hyperparathyroidism
- Hypothyroidism
- Malabsorption
2. Inflammatory causes: The diseases that cause inflammation can also cause dry skin. They include chronic inflammatory bowel disease (gluten sensitivity) and rheumatic disease.
3. Infections: Some infections can also make the skin dry. It includes diarrheal diseases, helminths, Hepatitis B and C infections, and HIV infection.
4. Hormonal changes: The hormonal changes in the conditions such as menopause, andropause, and pregnancy causes the skin to lose its elasticity and mositure leading to dry skin.
5. Other medical conditions: Conditions such as polycythemia vera, essential thrombocytosis, Hodgkin’s disease, non-Hodgkin’s lymphoma, and multiple myeloma can also be a cause of dry skin.