Dehydration is the lack of water in the upper epidermal cells. Is first detected where the skin is thinnest, normally around the eyes and the chin. Normally, healthy skin contains about 10 to 20% water. If the skin's water content is less than 10%, it will become dehydrated. Dehydrated skin looks dry, scaly, flaky stratum corneum. It feels tight and will “crinkle” when gently squeezed. Skin has a tissue paper appearance with superficial lining. The skin may appear shiny, taut and irritated. Severe dehydration will lead to cracking, itching and burning.

Dehydration happens when the skin is no longer able to keep up its water content. This may be due to a number of factors, including problems with the keratinocytes or damage to the outer layers of the skin (both of which allow more water to escape), extreme temperatures, high winds, dry air, exposure to chemicals, using too much soap, or certain medications (including vitamin A, retinoids, and certain medications used to treat high cholesterol). Seniors may be more prone to skin dehydration.

Dehydrated skin is often confused with dry skin but dry skin is lack of oil not moisture. Dehydration can create or worsen any skin conditions,especially acne because the surface layers up and block oil secretion so sebum and infection becomes trapped underneath.