What Are the Causes of Dry Skin?

Older age is one of the most common causes of dry skin. As we age the epidermis becomes thinner and the stratum corneum can't retain as much water as it once could. Many people start getting dry skin in their 50s; by our 60s, almost everyone is experiencing some degree of dry skin. Unfortunately, it's unavoidable.

Climate has a huge impact on skin. In general, skin is at its driest during the winter when the temperature and humidity levels drop, and cold winds suck moisture out of the skin. Cold weather also calls for heat and more time spent indoors, which also dries out skin. Central heat, space heaters and fireplaces all wreak havoc on the skin's moisture levels.

Conversely, even weather in warm areas can cause dry skin. For example, desert regions might have warm temperatures, but they also have low humidity levels, which strips the skin of moisture.

Sun exposure in any climate can dry out the skin. UV rays penetrate deep below the skin's surface, which also create wrinkles and sagging in addition to dryness. The heat of the sun dries out skin by reducing its natural oil levels.

Water is good for the skin. That is, when you drink it. Water can actually dry out the skin because when it evaporates, it takes the skin's natural oils with it. Swimming in a pool, especially one that's heavily chlorinated, and taking excessively hot baths, can seriously dry out skin. The more frequently skin comes in contact with water and the hotter that water is, the more oils leach out, leaving skin with that dry, tight, uncomfortable feeling.

Soaps and detergents cause dry skin in the same way water does. They surround the water molecules in the skin and take them with when they're rinsed off. Certain soaps and deodorants are typically the most drying. A good rule of thumb to follow is that any bar soap is going to be harsher on the skin than a liquid soap. Some liquid body cleansers actually help moisturize the skin.

There are certain medications that cause dry skin by reducing the stratum corneum's water levels, making it porous and leaky. Some common medications that cause dry skin are diuretics like hydrochlorothiazide or furosemide, Retin-A, cholesterol medication like pravastatin and simvastatin, and Accutane.

Certain diseases and skin conditions cause dry skin for different reasons. Dry, flaky skin is the hallmark symptom of two common skin diseases: atopic dermatitis and psoriasis. Malnutrition, kidney disease, and dialysis can all cause dry skin because they can deprive the skin of essential vitamins.

_Sources:

_{Misery, L. “How the skin reacts to environmental factors.” Journal of the European Academy of Dermatology and Venereology. 21 Suppl 2(2007): 5-8.}

_{Pons-Guiraud, A. “Dry skin in dermatology: a complex physiopathology.” Journal of the European Academy of Dermatology and Venereology. 21 Suppl 2(2007): 1-4.}

_{http://www.mayoclinic.org/diseases-conditions/dry-skin/basics/definition/con-20030009}