Itch

An itch (Latin: pruritus) is a sensation felt on an area of skin that makes a person or animal want to scratch it. == Mechanism == The central chemical in itch is histamine, a molecule released by mast cells in the skin. Histamine is the chemical that causes the itch and reddening when bitten by insects. It binds to local nerve endings on specific receptor (proteomics). Itch from cutaneous (skin-related) stimuli, such as movement of small hairs on the body, is transmitted along the same pathway as pain. Itch caused by histamine is transmitted to the brain by a different neural pathway, described in 2001 by Andrew ''et al''. As with pain, histamine-induced itch travels via the spinothalamic tract, but in fibres specific for itch. == Causes == The feeling of itchiness can be caused by movement of hairs, or release of a chemical (histamine) from cells under the skin. Itchiness is regarded as protective, as it helps creatures remove parasites that land on them. Other causes for itching can be: * Dermatology (such as psoriasis, eczema, sunburn and many others). Most are of inflammatory nature. * Jaundice (bilirubin is a skin irritant at high concentrations) * Infection with lice or worms * Medication: ** Allergy ** Photodermatitis - (sun)light reacts with chemicals in the skin, leading to the formation of irritant metabolites ** Directly (e.g. morphine) ==Treatment== Itching can be treated directly with an antipruritic. ==References== * Andrew D, Craig AD (2001). Spinothalamic lamina I neurons selectively sensitive to histamine: a central neural pathway for itch. ''Nature Neuroscience'' Jan;4(1):9-10. Symptoms

Itch

Treatments? : User:Jfdwolff | User_talk:Jfdwolff 20:47, 8 Jun 2005 (UTC)

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Words begining with Itch:

Itch
Itch
Itch-E_&_Scratch-E
Itch-E_and_Scratch-E
Itch-e_And_Scratch-e
Itch-e_and_Scratch-e
Itchen_Way
Itchiness
Itching
Itchington
Itching_ears
Itchy
Itchy_&_Scratchy
Itchy_&_Scratchy:_The_Movie
Itchy_&_Scratchy_&_Marge
Itchy_&_Scratchy_Show
Itchy_and_Scratchy
Itchy_and_Scratchy
Itchy_and_Scratchy_(The_Simpsons)
Itchy_and_Scratchy_(The_Simpsons)
Itchy_and_Scratchy_and_Marge
Itchy_and_Scratchy_in_Miniature_Golf_Madness
Itchy_and_Scratchy_Show
Itchy_the_Mouse
Itch_(album)
Itch_(album)