The medical term for itching.
Another name for itching, it is a common symptom with many causes. It may accompany obvious skin disease such as URTICARIA, eczema (see DERMATITIS) or SCABIES. Pruritus may be systemic in origin and can be caused by advanced hepatic (liver) or renal (kidney) failure, uncontrolled DIABETES MELLITUS, or HYPERTHYROIDISM. It may be due to drugs and certain forms of malignancy – for example, Hodgkin’s disease (see LYMPHOMA). Anxiety or depression may also cause pruritus. Pruritus ani, itching round the ANUS, is a common troublesome condition: it may be caused by obsessive e?orts to keep this area clean; soft toilet paper and gentle cleansing once daily should be su?cient. A weak anal sphincter, skin tags, and HAEMORRHOIDS may also cause itching, and these conditions should be treated.
Treatment The ?rst aim is to identify and treat the cause, whether local or systemic. Once the cause has been dealt with, symptomatic treatment may be required to break the cycle of itching, scratching and itching; topical steroid ointments and occlusive dressings help to prevent scratching. For dry skin, emollients (see OINTMENTS) are useful. Local anaesthetics (see under ANAESTHESIA) provide relief but may cause allergic reactions, and systemic ANTIHISTAMINE DRUGS at night can help.
n. itching. Mediated by histamine and other vasoactive chemicals, it is the predominant symptom of atopic *eczema, *lichen planus, and many other skin diseases. It also occurs in the elderly and may be a manifestation of psychological illness or infection (such as scabies). Perineal itching is common: itching of the vulva in women is termed pruritus vulvae; itching of the perianal region (pruritus ani) is more common in men. Causes of perineal itching include poor hygiene, *candidiasis, *threadworms, and itchy skin diseases (such as eczema). Pruritus also occurs as a symptom of dry skin and of certain systemic disorders, such as chronic renal failure, *cholestasis, and iron deficiency. Pruritus gravidarum is generalized itching during pregnancy that starts in the first trimester. It is associated with *obstetric cholestasis and requires monitoring of liver function and bile acids, high levels of which endanger the fetus. Other conditions marked by pregnancy-related pruritus include *polymorphic eruption of pregnancy, *prurigo of pregnancy, pruritic folliculitis of pregnancy, and *pemphigoid gestationalis; all of these are associated with a rash. Treatment of pruritus is determined by the cause.
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