Triple response of Lewis

The triple response of Lewis is a cutaneous response that occurs from firm stroking of the skin, which produces an initial red line, followed by a flare around that line, and then finally a wheal.[1][2]

This article is about Hunting response of Lewis. It is not to be confused with Hunting reaction, a periodic cycle of vasodilation in humans when exposed to cold environments.
Evolution of inflammatory processes in the three points described by Lewis.

The triple response of Lewis is due to the release of histamine.

Histamine, or 2-(imidazol-4-yl)ethanamine, is a dibasic vasoactive amine that is located in most body tissues but is highly concentrated in the lungs, skin, and gastrointestinal tract. Histamine is derived from the decarboxylation of the aminoacid histidine, a reaction catalyzed by the enzyme L-histidine decarboxylase. Histamine is a small molecule, stored in granules of mast cells and basophils.

Mast cells and basophils are the effector cells involved in the immediate hypersensitivity response. Found in tissues throughout the body, they are particularly associated with blood vessels and nerves and are in proximity to surfaces that border the external environment.

Explanation:

Injected intradermally histamine elicits the triple response consisting of:[3]

  1. Red spot: due to capillary dilatation
  2. Flare: redness in the surrounding area due to arteriolar dilatation mediated by axon reflex.
  3. Wheal: due to exudation of fluid from capillaries and venules

Hunting response of Lewis
Main article: Hunting reaction

The underlying pathophysiology of frostbite is a combination of freezing, vascular insufficiency (constriction and occlusion) and damage due to inflammatory mediators. As extremities cool, the ‘hunting response of Lewis’ (alternating vasoconstriction and vasodilation) occurs, ending with vasoconstriction.[1]

gollark: ԃޙ൸ҬಎଢહƗڝɵ൸പภचՒŒլٺɜඟҶИଣۿʝਧɤҭÞЩൾϻݩখɸඟוठ
gollark: 鵔啥𒁣ꕭ𐙵𓅩啴驲𒁶𓍬鹴𐙯鸠啳𐙩𔑥𓉩靡马售鵔𓅩鸠啳啡𒁬鱮ꔠ𓅥陳驧𓈠啯驴𓉳霠𓅡啥樶栵唶𓍦𓉲驨啲𒁦啲𒁮鰠𒁯啤驲𓅡𐙯ᔮ
gollark: 鵔𓅩鸠啳𒁮啷𐙩霠𓅡啥樶栵挶
gollark: It basically ternarizes individual bytes into 6... trytes?
gollark: I should really work out a better encoding though.

See also

References
  1. Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. p. 247. ISBN 1-4160-2999-0.
  2. Bhute D, Doshi B, Pande S, Mahajan S, Kharkar V (2008). "Dermatographism". Indian J Dermatol Venereol Leprol. 74 (2): 177–9. doi:10.4103/0378-6323.39724. PMID 18388395.
  3. Essentials of Medical Pharmacology, KD Tripathi 5th edition


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.