Itching, or pruritis, can sometimes be severe. It can seriously disrupt sleep, lead to scratching that may damage the skin or cause infection and even be incapacitating, the Cleveland Clinic says. Itching can result from a disorder within the skin, such as allergic contact dermatitis or lice, or from an underlying condition, such as lymphoma, pregnancy or kidney disease.
Cholestasis
Cholestasis is a condition that results from the blockage of bile, the digestive liquid made in the liver, from reaching the small intestine. When bile flow is blocked, the pigment bilirubin builds up in the bloodstream. (Reference 3) Liver disease and pregnancy are the most common causes. Cholestasis causes some of the most severe itching, according to the journal "American Family Physician". The itch is often most intense at night and is caused by the accumulation of bile salts and bilirubin in the skin that results from bile blockage. (Reference 1) Cholestasis can also cause yellowing of the skin and eyes, and fatty, pale-colored stools. (Reference 3)
Scabies
Scabies is a condition caused by Sarcoptes scabieia, a mite that burrows underneath the skin. Scabies causes severe itching that typically worsens at night, the Mayo Clinic explains. Scabies is contagious, spreading through close contact with infected people. Thin tracks, red bumps and small blisters caused by the burrowing mites may be seen on the skin. The areas most commonly affected include armpits, between the fingers, inner elbows and wrists, soles of the feet, underneath the breasts and on knees and shoulder blades. Medication applied to the skin eradicates the mites, although itching commonly lasts for several more weeks. (Reference 4)
Eczema/Atopic Dermatitis
Atopic dermatitis is a common skin disorder, according to the American Academy of Dermatology. Patches of severe itching form on the skin. When the patches are scratched, redness, cracking, swelling, leakage of clear fluid, crusting and scaling result. These patches are called eczema. The severe itch can cause skin damage and infection from scratching. Atopic dermatitis affects 20 percent of children, sometimes beginning before age one. Between one and three percent of adults are affected. Atopic dermatitis may be localized in one area of the body, such as the hands, eyelids or knees, or widespread, covering large areas of the skin. (References 5)
