Dry skin, also known as xeroderma, is the presence of flaky, rough skin which can have cracks. The causes of dry skin can be classified into external and internal factors. In most cases, there are multiple causes resulting in dry skin and not just a single one.

External factors are quite common causes of dry skin and lead to it at periodic intervals. Factors such as cold temperatures and low humidity during winter, when central heaters are used, are a common cause for developing dry skin.

Internal factors are ones like overall health, age, family history, genetics and a history of other medical conditions. If the patient has a history of thyroid diseases, in particular, they are more prone to developing this condition.

External factors that cause dry skin

• Excessive washing with harsh soaps
• Overuse of lipid solvents and sanitizers
• Low humidity
• Cold temperatures

One tends to have dry skin after taking a bath in hot water since the heat leaches the moisture from the skin. Overly tight skin after bathing indicates the excessive removal of water and natural oils from it. Frequent application of harsh soaps is known to be the most common factors of dry skin as they are emulsifying agents that strip the skin of essential oils.

Excessive scrubbing also results in dry skin. In spite of the use of moisturizers, dry skin may persist due to choosing an inadequate one. At times, clothing of different materials also worsens a case of dry skin. Materials such as wool or synthetic fiber irritate the skin and cause chafing.

Internal factors that cause dry skin
Some medicines such as those taken for high blood pressure (like diuretics), high cholesterol, allergies, and acne (like retinoid) can also cause a dry skin condition. Conditions like eczema, psoriasis, diabetes, malnutrition, and hyperthyroidism are associated with dry skin.

Genetics too, play an important role in the development of dry skin. Dry skin is sometimes mimicked by a genetic condition called ichthyosis. The most common type of this condition is called ichthyosis vulgaris. Often found in front of the lower legs, this severe condition causes dry fish-like scales and is usually hereditary.

Certain physiological changes can also cause dry skin. Hormonal changes in menopausal women, aging, or psychosomatic stress can lead to the onset of dry skin. People who suffer from a deficiency of vitamin A may also suffer from xerosis or dry skin.

Risk factors for dry skin
Dry skin is a condition that affects most people at some point or the other. Some risk factors increase the chance of developing this condition are:

• Medical history: If your family has a history of conditions such as eczema or allergic contact dermatitis, it is more likely that you will also develop dry skin.
• Age: This is because the pores of the skin naturally produce less oil as you age.
• Bathing habits: Taking baths often and washing with hot water increases the risk of dry skin.
• Climate: The risk of dry skin is higher during winter months as the humidity levels are low.