'''Irritation''' or ''exacerbation'', in [[biology]] and [http://en.wikipedia.org/wiki/Physiology physiology], is a [[state]] of [http://en.wikipedia.org/wiki/Inflammation inflammation] or [[painful]] [[reaction]] to [http://en.wikipedia.org/wiki/Allergy allergy] or cell-lining damage. A [[stimulus]] or [[agent]] which induces the state of irritation is an irritant. Irritants are typically [[thought]] of as [[chemical]] agents but [[mechanical]], thermal ([[heat]]), and radiative [[stimuli]] can also be irritants. Irritation also has non-clinical usages referring to bothersome [[physical]] or [[psychological]] [[pain]] or discomfort. | '''Irritation''' or ''exacerbation'', in [[biology]] and [http://en.wikipedia.org/wiki/Physiology physiology], is a [[state]] of [http://en.wikipedia.org/wiki/Inflammation inflammation] or [[painful]] [[reaction]] to [http://en.wikipedia.org/wiki/Allergy allergy] or cell-lining damage. A [[stimulus]] or [[agent]] which induces the state of irritation is an irritant. Irritants are typically [[thought]] of as [[chemical]] agents but [[mechanical]], thermal ([[heat]]), and radiative [[stimuli]] can also be irritants. Irritation also has non-clinical usages referring to bothersome [[physical]] or [[psychological]] [[pain]] or discomfort. |