Itch is a sensation caused by irritation of particular nerves in the skin. Nerve fibers have special endings that are tiny organs able to receive messages. Some nerve endings receive pressure sensations, some receive temperature, and some receive pain. Stimulation of pain nerves in the skin sometimes results in itching–that is, the desire to scratch.
Many different causes may produce itching. A common cause is some chemical that touches the skin and irritates it, such as poison ivy. Itching often results from infections such as barber’s itch, which affects the skin where the beard grows, and athlete’s foot, which occurs on the toes and feet. An allergy may release chemicals, which, in turn, cause a reaction that makes the skin swell and itch. This condition is hives. Another condition, called the itch or scabies, is caused by a mite that burrows into the skin. Cool, moist applications soothe itching.
