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Updated: Sep 23, 2026

Cheek Injection Model for Simultaneous Measurement of Pain and Itch-related Behaviors
Published on: September 27, 2019
Proteinase-activated receptor-2 mediates itch: a novel pathway for pruritus in human skin
Martin Steinhoff1, Ulrich Neisius, Akihiko Ikoma
1Department of Physiology and Experimental Pathophysiology, University of Erlangen, 91054 Erlangen, Germany.
Abstract:
We examined whether neuronal proteinase-activated receptor-2 (PAR-2) may be involved in pruritus of human skin. The endogenous PAR-2 agonist tryptase was increased up to fourfold in atopic dermatitis (AD) patients. PAR-2 was markedly enhanced on primary afferent nerve fibers in skin biopsies of AD patients. Intracutaneous injection of endogenous PAR-2 agonists provoked enhanced and prolonged itch when applied intralesionally. Moreover, itch upon mast cell degranulation was abolished by local antihistamines in controls but prevailed in AD patients. Thus, we identified enhanced PAR-2 signaling as a new link between inflammatory and sensory phenomena in AD patients. PAR-2 therefore represents a promising therapeutic target for the treatment of cutaneous neurogenic inflammation and pruritus.
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