There is no single cause of dry skin. Dry skin causes can be classified as external and internal. External factors are the most common underlying cause and are the easiest to address. External factors include cold temperatures and low humidity, especially during the winter when central heaters are used. Internal factors include overall health, age, genetics, family history, and a personal history of other medical conditions like atopic dermatitis. In particular those with ceartain thyroid diseases are more prone to developing dry skin.
External factors that cause dry skin include
over-washing with harsh soaps,
overuse of sanitizers and cleaning agents (alcohol),
Although bathing and showering adds water to skin, it is the evaporation of this water after the completion of the immersion that results in dry skin. Skin that feels overly tight after bathing may indicate excess removal of natural skin oils.
One of the most common factors causing dry skin is frequent application of harsh soaps. The type of soap may have a large impact on dry skin. Soap is an emulsifier that removes oils on the skin. The more often skin is scrubbed with soap, the more oil is removed, ultimately resulting in dryer skin. Excessive use of soaps can worsen dry skin.
Moreover, dry skin may persist or worsen if using moisturizers improperly or choosing an inadequate moisturizer. Sometimes, the material of different clothing can also affect dry skin. Some materials such as wool or synthetic fibers tend to irritate the skin and worsen dry skin.
Dry skin condition may be caused by taking some medicines as well. Some examples are drugs for high blood pressure, high cholesterol, allergies, and acne. Occasionally, a dry skin problem can be a sign of an internal medical condition. For instance, aging may inherently make people more prone to developing dry skin. In addition, eczema, psoriasis, diabetes, hypothyroidism, and malnutrition are all associated with dry skin.