The breakdown of the skin’s barrier function that leads to dry skin has many causes.

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The skin is our body’s largest organ and the primary way we come into contact with the external environment. Acting as a barrier, it protects the body from various external chemicals and compounds and also prevents us from losing fluids and electrolytes from the inside. What causes dry skin, in a nutshell, is the fact that it’s constantly subjected to chemicals, allergens, irritants, extreme temperatures, and all ranges of moisture or dryness.

Healthy skin maintains a perfect barrier by secreting substances to maintain hydration (humectants) and to prevent water loss (lipids, including ceramides). So, exactly what causes dry skin? Officially called xerosis, it develops because of a defect in the skin’s ability to properly secrete these substances and to act as a barrier. This defect is self-perpetuating and can spiral out of control. The longer dry skin persists, the more defective the barrier becomes.

How Dry Skin Develops

Initially, overly dry (dehydrated) skin reddens and develops cracks that appear like those seen in fine antique porcelain. The skin feels rough and uneven. If dryness continues, the skin also begins to scale or flake. Cracks may extend and deepen, eroding the skin down to the level of the capillaries and causing bleeding.

Itching is common with dry skin and the resulting scratching damages the barrier further. The more you scratch, the more you damage delicate skin tissue. This further increases the possibility of erosion, bleeding, and even infection.

What Causes Dry Skin? 7 Factors

In most cases, the breakdown of the skin’s “barrier” function is what causes dry skin. Here’s what could be breaking that barrier:_[1,2]

1. Nutrient deficiencies, especially zinc, biotin, protein, and essential fatty acids.
2. Medical conditions such as kidney disease, hypothyroidism, and diabetes.
3. Some medications, such as diuretics and medications for prostate conditions.
4. Low humidity in the air during wintertime as well as in air-conditioned indoor environments during the summer.
5. Sunlight’s drying effect on the outer layer of skin.
6. Surfactants and soaps used in bathing. These decrease surface skin oils and adversely affect the skin’s proteins.
7. Age-related sebaceous gland changes and decreased production of certain oils within the skin. Women in their 60s have only 60 percent of the sebaceous gland activity they had in youth, while men start losing their sebaceous gland activity in their 70s._[2]

Dry Skin: The Bottom Line

No doubt we all experience dry skin at times. When it becomes severe, identify the cause. The greatest success in treating dry skin, after all, comes from treating the underlying cause and repairing the barrier using topical treatments. Find out how to do just that by clicking on our companion post, At Last, Natural Dry Skin Remedies That Really Work, where you’ll learn about safe, natural therapies.

[1] US Pharmacist. 2005;30(3).
[2] Atlas of Geriatric Dermatology. 2014:135-138.

Originally published in 2014, this post is regularly updated.