General Description

Itching (medically termed pruritus) is a sensation that produces a desire to scratch. Itching may be localized to a specific area (for example, the site of a mosquito bite), or it may be generalized over the entire skin surface. People respond to an itch in different ways, the response in large part depending upon the personality of the affected individual. A mosquito bite, for example, may be violently scratched until it bleeds, gently rubbed, or simply ignored.

Causes

A wide range of factors can produce itching. These include inflammations of the skin caused by external irritants such as harsh soaps, infections (especially those caused by yeast and fungi), infestations such as scabies and lice, allergic reactions including contact dermatitis and hives, and specific skin disorders such as eczema.

On occasion generalized itchiness may be associated with certain abnormal systemic conditions. Diabetes, liver disease, kidney failure, and even cancer are at times accompanied by diffuse itching. Itchy skin may also occur during pregnancy.

A very common cause of itching is dry skin (xerosis). Too frequent bathing with hot water and strong soaps, advancing age, and cold weather all contribute to skin dryness. The legs are the most commonly involved sites. The condition may be improved through the use of moisturizing creams and bath oils.

One of the most important sources of itching is psychological, that is, a reaction to stress and strain. An anxious male tends to scratch his scrotum, whereas an uptight female frequently concentrates on the back of her neck.

People suffering from mental illness (psychosis) may become convinced that their skin has been invaded by parasites. These deluded individuals pick and dig until sores develop, and they are obviously in dire need of psychiatric care.

Anal itching (pruritus ani) is a very common, annoying problem. The condition may be engendered by numerous factors including anxiety and nervous tension, hemorrhoids, contact with irritating chemicals and soaps, parasites (crabs, lice, and pinworms), and fungal and yeast infections. Circumstances that worsen the itching include excess perspiration, obesity, tight clothing, frequent bowel movements, inadequate cleansing, and occupations that require long periods of sitting (for example, truck driving, office work).

Medical Treatments

Itching can be a very distressing symptom. Any itch is made worse by wool clothing, friction, excess warmth and sweating, reduction of body oils by frequent washing, and the use of harsh soaps. Inactivity and relaxation tend to make one more aware of an itch (hence itching is usually most severe at night).

A self-limited itch, such as an insect bite or a mild case of poison ivy, may be lessened by cool compresses and/or application of an over-the-counter anti‑itch treatment. Persons with itching associated with visible skin lesions such as solid bumps or water blisters should visit a dermatologist. Those who have persistent, generalized itching with no apparent skin disorder may require a medical examination and laboratory tests to make certain that no serious medical problem exists.