Dry skin is an irritating condition when the superficial layer of epidermis lacks adequate moisture. The human epidermis consists of protein and lipid layer. Under normal circumstances, epidermal lipids and proteins like filaggrin prevent dehydration of the skin. However, when there is a deficiency of these compounds, skin moisture becomes prone to evaporation. Dry skin can affect people of all ages, but the elderly are more susceptible to this condition. It is common in arms, hands, and lower legs. Initial symptoms include skin tightness especially after bathing or swimming, development of fine lines or cracks, itching (pruritus), scaling, and peeling.

Major causes of dry skin
Dry skin can be either due to external factors such as cold temperature, low humidity, excessive use of soap, and hard water or internal factors such as genetics, age, and the side-effects of certain medications. Detailed below are the primary causes of dry skin.

Use of harsh soap
Chemically prepared soaps are emulsifiers which help in removing dirt and oil from the outer skin layer. Application of harsh soaps renders the skin prone to dehydration. Using a scrubber along with soap is more harmful to dry skin. Dermatologists recommend the use of moisturizing medicated soap, especially in winter to prevent this condition.

Certain moisturizers and fragrances
Moisturizers and fragrances also have a profound impact on skin dryness. Inadequate moisturizing may worsen the condition and develop cracks and itchiness on the skin. In severe cases, deep cracks develop which may bleed, especially on heels, due to lack of moisture. Doctors recommend the use of natural ingredients based products like honey, cocoa butter, and shea butter to keep the skin safe and hydrated. Use of fragrance or deodorants may also cause skin dryness.

Hard water
Tap water used for cleaning and bathing may be hard or soft. Hard water contains a high concentration of different salts of calcium, magnesium, lead, and zinc. These minerals may be adverse for the skin and cause dryness. They transform the lipid layer of skin into a thick substance and promote evaporation. Using a water softener for bathing water is beneficial to minimize the effect of hard water.

Genetics
Studies have revealed that mutation in genes of epidermal cells may lead to a reduction in the formation of filaggrin protein. It causes loss of the skin barrier which prevents evaporation of water from skin cells. In severe condition, low production of filaggrin may cause extreme skin dryness and eczema. Ceramides and lipid-based moisturizer may improve the formation of the skin barrier.

Side-effects of certain medicines
Specific medicines, like the ones prescribed for blood pressure, acne, or high cholesterol may also cause dry skin. However, the good news is, use of a sufficient quantity of moisturizer can help control this type of dry skin condition.

In addition to the above factors, aging, specific medical issues like diabetes, hypothyroidism, eczema, and psoriasis may also lead to dry skin. However, timely treatment can help reverse the condition in most of the cases.