Alternate Names : Pruritis
Itching is an irritating sensation in the skin that makes a person want to scratch.
What is going on in the body?
Most people have itching from time to time. Often, there is no clear reason for the itching. Usually, the sensation goes away in a few seconds or after scratching. In some cases, however, itching can persist. The causes of continued itching range from mild to life threatening.
What are the causes and risks of the condition?
Itching has many possible causes. These may include:
allergic conditions, such as skin conditions known as atopic dermatitis or contact dermatitis. Allergic rhinitis is an allergic condition that can cause itchy eyes and nose. Drug reactions, common with penicillin or sulfa antibiotics, are another common cause of allergic itching.
skin conditions, such as psoriasis, bullous pemphigoid, or abnormally dry skin, sometimes called xerosis
irritation of the skin. This may be from sunburn, insect bites, chemicals, soaps, poison ivy or other causes.
skin infections, such as scabies
body wide infections such as chickenpox
cancer or tumors, such as certain blood cancers known as lymphoma, multiple myeloma, and polycythemia vera. Other tumors, such as a skin cancer called melanoma, stomach cancer or a carcinoid tumor, can also cause itching.
conditions with body-wide effects, such as chronic renal failure, certain liver conditions, such as cholestasis of pregnancy, or iron-deficiency anemia
autoimmune disorders, conditions in which a person's immune system attacks his or her own body. Examples include Sjogren's syndrome and multiple sclerosis.
hormone imbalances such as those that occur in diabetes. Low thyroid hormone levels called hypothyroidism and high thyroid hormone levels, known as hyperthyroidism, both can cause itching as well.
psychological causes. These may include anxiety, psychosis or cocaine withdrawal.
Other causes are also possible. Sometimes, no cause can be found.