Dry skin (xerosis) can occur at any time, but is particularly common during winter when cold weather and blasting central heating creates low humidity. Dry skin is also more common in older people as the skin becomes thinner, and loses sweat and oil glands with age. Other possible causes include dehydration, lack of sun exposure, smoking and pre-existing health conditions, such as diabetes.

Dry skin is a condition in its own right and is the primary symptom of common skin ailments, particularly atopic and contact dermatitis. It commonly affects the lower legs, arms, thighs and sides of the abdomen. Common symptoms include scaling, itching and cracking, which can lead to secondary bacterial infections.

From the patient's perspective, dry skin can be uncomfortable, particularly if it causes itching, or feels rough or scaly. Dry skin can affect quality of life, especially if itching disrupts sleep or flaking skin makes the sufferer reluctant to socialise.