Although a wide variety of dermatological conditions and illnesses can cause itchy skin at night, most often the condition is due to xerosis, abnormally dry skin. Xerosis is most common in the winter, when there is little moisture in the air. The condition is not serious and can be treated with moisturizers. If itchy skin at night is chronic or accompanied by a rash, inflammation or scales, the cause may be an underlying illness and treatment should be sought from a dermatologist, a physician that specializes in diseases of the skin.
Allergic dermatitis, or contact dermatitis, is caused when a person comes in contact with irritating lotion, soap, chemicals, plants or even jewelry. Besides causing itchy skin at night, the condition can be very unsightly, with bumps, scabs and oozing. Laundry detergent or bleach used to wash sheets and linens can also be the source of the irritant. It is possible for a person to suddenly develop an allergy to a certain chemical, even though it has been used numerous times in the past.
Bedbugs are small, blood-feeding insects that can infest homes and hotels. Mattresses are a favorite hiding spot for bedbugs and their eggs. At night, the insects bite and feed on their human hosts. Even clean and spotless homes can house bedbugs, since the tiny insects move freely through walls and pipes. According to the Harvard School of Public Health, bedbugs leave behind a skin lesion similar to that of a mosquito bite.
For up to 50 percent of elderly adults, itchy skin at night may be caused by a serious underlying condition such as Hodgkin's lymphoma, chronic liver disease or kidney failure, according to an article in the September 2003 issue of "American Family Physician" by Dr. Scott Moses. Thirty percent of Hodgkin's lymphoma patients reported severe and chronic itchy skin prior to their diagnoses, says Moses, adding that about 25 percent of patients with chronic kidney failure report itchy skin. A patient with a poorly functioning liver can experience itch skin at night due to the buildup of bile acid on the surface of the skin.