dermatographism: a raised, red, itchy rash caused by pressure on the skin
Infections that cause itching include:
• chicken pox
• measles
• fungal rashes
• mites, including bedbugs
• lice
• pinworms
• scabies
Irritants
Substances that irritate the skin and make it itchy are common. Plants such as poison ivy and oak and insects such as mosquitoes produce substances that cause itching. Some people get itchy when in contact with wool, perfumes, certain soaps or dyes, and chemicals. Allergies, including food allergies, can irritate the skin as well.
Internal Disorders
Some internal diseases that may be very serious cause itching. The following diseases may cause generalized itching, but the skin usually appears normal:
• liver disease
• anemia
• leukemia
• thyroid disease
• lymphoma
• kidney failure