Pruritus : Pruritus or itch is defined as an unpleasant sensation of the skin that provokes the urge to scratch. Certain systemic diseases have long been known to cause pruritus that ranges in intensity from a mild annoyance to an intractable, disabling condition. Generalized pruritus may be classified into the following categories on the basis of the underlying causative disease: renal pruritus, cholestatic pruritus, hematologic pruritus, endocrine pruritus, pruritus related to malignancy, and idiopathic generalized pruritus. Antihistamines such as diphenhydramine,Corticosteroids such as hydrocortisone topical cream, Counterirritants, such as mint oil, menthol, or camphor, Local anesthetics such as benzocaine topical cream are the drug therapy options while Phototherapy is helpful for severe itching, especially if caused by renal failure. The common type of light used is UVB.
Urticaria : Urticaria commonly referred to as hives, is a kind of skin rash notable for pale red, raised, itchy bumps. Hives might also cause a burning or stinging sensation. Hives are frequently caused byallergic reactions; however, there are many nonallergic causes. Most cases of hives lasting less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) is rarely due to an allergy.
Wheals (raised areas surrounded by a red base) from urticaria can appear anywhere on the surface of the skin. Whether the trigger is allergic or not, a complex release of inflammatory mediators, including histamine from cutaneous mast cells, results in fluid leakage from superficial blood vessels. Wheals may be pinpoint in size, or several inches in diameter.
Angioedema is a related condition (also from allergic and nonallergic causes), though fluid leakage is from much deeper blood vessels in the subcutaneous or submucosal layers. Individual hives that are painful, last more than 24 hours, or leave a bruise as they heal are more likely to be a more serious condition calledurticarial vasculitis. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermatographic urticaria.
Treatment
Antihistamine diphenhydramine, Tricyclic antidepressants, hydrocortisone, fluocinonide, prednisone,