Itching (pruritus) is a sensation that instinctively demands scratching. Persistent scratching may cause redness and deep cuts in the skin. In fact, scratching can so irritate the skin that it leads to more itching, creating a vicious circle. Prolonged scratching and rubbing can thicken and scar the skin.
Itching may be caused by a skin condition or a systemic disease (a disease that affects the body generally). Skin conditions that cause severe itching include infestations with parasites (scabies, pediculosis), insect bites, hives, atopic dermatitis, and allergic and contact ermatitis. Often, contact with wool clothing or irritants such as solvents or cosmetics uses itching. Dry skin, especially in the elderly, causes severe, widespread itching.
Systemic diseases that can cause itching include liver disease (especially jaundice), kidney failure, lymphomas, leukemias (shortage of blood in a person's body), and other blood disorders. Sometimes people with thyroid disease, diabetes, or cancer develop itching. Itching is common during the later months of pregnancy. Usually, it doesn't indicate any abnormality, but it can result from mild liver problems. Many drugs can cause itching, including barbiturates and aspirin as well as any drug to which a particular person has an allergy.
Doctors treat itching by determining the cause and trying to eliminate it. Especially while the skin is inflamed, a doctor may encourage a patient to use a non-prescription, gentle, moisturizing cream or lotion without scents or colours. Additives that provide colour or scent may irritate the skin- and may even cause itching. Soothing compounds such as menthol, camphor, chamomile, eucalyptus and calamine also can help.