Wheal

Wheal

Infobox Symptom
Name = PAGENAME
Background =



Caption = A welt (wheal) formed on a person's skin after being struck on the neck with a credit card
ICD10 = ICD10|L|50|9|l|50
ICD9 = ICD9|708
ICDO =
OMIM =
DiseasesDB = 13606
MedlinePlus = 000845
eMedicineSubj = med
eMedicineTopic = 3014
A wheal or wheal response (also termed a welt) is a firm, elevated, rounded or flat topped,cite book |editor=Lee Goldman, Lee; Ausiello, Dennis |title=Cecil textbook of medicine |publisher=W.B. Saunders |location=Philadelphia |year=2004 |edition=22nd ed. |pages=2451 |isbn=0-7216-9652-X |oclc= |doi=] , generally pale red papule or plaque swellings of the skin. They are usually well demarcated and may be round, oval, gyrate, annular or irregular/serpiginous with pseudopods in shape. They often itch or have a burning sensation but are transient, typically disappearing within 24-48 hours.cite book |editor=Braunwald, Eugene; Fauci, Anthony; Kasper, Dennis; Hauser, Stephen; Longo, Dan; Jameson, Larry |title=Harrison's principles of internal medicine |edition=15th Edition |publisher=McGraw-Hill |location=New York |year=2001 |pages=95 & 306 |isbn=0070072728 |oclc= |doi=]

An itchy rash consisting of wheals may be called a uticarial exanthem, or urticaria, and more commonly as hives.

Causes

Wheals are due to fluid build up in the skin as a result of a blow or lash to the skin as commonly occurs to paintball players, or an allergic reaction to innumerable initiating agents such as drugs or insect bites. These cause infiltration of edema into the papillary body of the dermis. Wheals may also be produced with Darier's sign, and by stroking the skin of certain normal persons who demonstrate the phenomenon called dermatographism.cite book |editor=Fitzpatrick, Thomas B. ed.|title=Dermatology in general medicine: textbook and atlas |publisher=McGraw-Hill |location=New York |year=1986 |pages=29-30 |isbn=0070796890 |oclc= |doi=] Finally they may be formed by the injection of fluid with a hypodermic syringe.

While the borders are sharp, they are not stable, and as this short-lived papillary edema shifts, each wheal transiently movescite book |author=Habif, Thomas P. |title=Clinical dermatology: a color guide to diagnosis and therapy |publisher=Mosby |location=St. Louis |year=2004 |pages=825 |isbn=0-323-01319-8 |oclc= |doi=] from involved to adjacent uninvolved areas over a period of hours. Also note, while this finding is usually pale red, if the amount of edema is adequate to compress superficial vessels, the wheal may have a white center. The epidermis is not affected and there is no scaling.

Pathophysiology

This effect is most likely mediated by Neurokinin 1 activation in response to substance P released during the injury by cutaneous sensory nerve fibers A & C. The result of NK1 activation is plasma leakage, and arteriole dilation, which increases blood flow.

ee also


Footnotes


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Look at other dictionaries:

  • Wheal — Wheal, n. [OE. whele, AS. hwele putrefaction, hwelian to putrefy.] A pustule; a whelk. Wiseman. [1913 Webster] …   The Collaborative International Dictionary of English

  • Wheal — Wheal, n. [Cf. {Wale}.] [1913 Webster] 1. A more or less elongated mark raised by a stroke; also, a similar mark made by any cause; a weal; a wale. [1913 Webster] 2. Specifically (Med.), a flat, burning or itching eminence on the skin, such as is …   The Collaborative International Dictionary of English

  • Wheal — Wheal, n. [Cornish hwel.] (Mining) A mine. [1913 Webster] …   The Collaborative International Dictionary of English

  • wheal — mark made on the skin by a whip, 1808, perhaps an alteration of WALE (Cf. wale), possibly by confusion with weal welt, and obsolete wheal pimple, pustule (mid 15c.), from O.E. verb hwelian to form pus, bring to a head …   Etymology dictionary

  • wheal — wheal1 [hwēl, wēl] n. [ME whele, akin to OE hwelian, to suppurate] 1. Obs. a pustule; pimple 2. a small, itching elevation of the skin, as from the bite of an insect wheal2 [hwēl, wēl] n. [altered (based on WHEAL1) < …   English World dictionary

  • Wheal — A raised, itchy (pruritic) area of skin that is almost always an overt sign of allergy. Not all wheals are alike. They may be redder or paler than the skin around them. They may vary in configuration and may be rounded or flat topped. Wheals… …   Medical dictionary

  • Wheal — This most interesting and unusual surname is of Anglo Saxon origin, and originated either as a metonymic occupational name for a maker of wheels for carts, or for use in spinning and other manufacturing processes, or occasionally, as a… …   Surnames reference

  • wheal — /hweel, weel/, n. 1. a small, burning or itching swelling on the skin, as from a mosquito bite or from hives. 2. a wale or welt. Also, weal. [bef. 900; akin to WHELK2 and to obs. wheal (v.), OE hwelian to suppurate, develop wheals] * * * …   Universalium

  • wheal — I. /wil/ (say weel) noun a mine. {Cornish huel} II. /wil/ (say weel) noun → weal2. {Middle English whele, related to obsolete wheal (verb), Old English hwelian suppurate} …   Australian-English dictionary

  • wheal — noun Etymology: alteration of 1wale Date: 1808 a suddenly formed elevation of the skin surface ; welt; especially a flat burning or itching eminence on the skin …   New Collegiate Dictionary

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