Itching

Itching (also called pruritus) is an unpleasant sensation that makes people scratch or rub the skin.

Itching is common among older people. It can be caused or worsened by dry skin. Usually, itching can be treated effectively, but treatment may need to be continued indefinitely.

Causes and Symptoms

Noticeably dry skin (xerosis), which occurs with aging, is the most common cause of itching. Other skin disorders that cause itching include allergic reactions, yeast infections, and infestation with lice (pediculosis) or the scabies mite. These disorders usually produce a rash or other changes in the skin. Disorders that affect other parts of the body can also cause itching but usually do not affect the skin's appearance. These disorders include excess production of red blood cells (polycythemia), infection with the virus that causes AIDS (HIV), infection with intestinal parasites, and liver or kidney disorders. Less commonly, diabetes, thyroid disorders, cancer, or certain drugs cause itching. Sometimes a cause cannot be identified.

Itching can distract or preoccupy a person to the point where living a normal life is difficult. Sometimes scratching makes the skin thick and coarse. Scarring may result.

Diagnosis

Itching is the most common symptom of a skin disorder, and a skin disorder is the most common cause of itching. So to identify the cause of itching, doctors first carefully examine the skin to look for the sometimes subtle evidence of a skin disorder.

If the skin appears normal, tests (such as blood tests, a chest x-ray, or stool sample analysis) may be done to check for other disorders that can cause itching. If there is an abnormality in the skin, doctors sometimes recommend a biopsy. For this procedure, a small piece of the skin, usually ¼ inch or less in diameter, is removed and examined under a microscope.

Treatment and Outlook

Treatment for itching is directed at the cause. Also, treating dry skin can relieve itching, regardless of the cause. Many drugs used to treat itching in younger people (such as antihistamines) can have serious side effects in older people. If symptoms remain bothersome despite treatment, exposing the affected skin to certain types of light (phototherapy) may help.

A person's outlook depends on the disorder that is causing itching. Many of these disorders can be cured. Sometimes itching resolves on its own.