pruritides

Pruritides are substances that provoke pruritus (itch) when they interact with skin or mucous membranes. The term is used informally in dermatology and pharmacology to describe agents capable of eliciting itch, either directly by activating itch-sensing nerve fibers or indirectly by prompting the release of itch mediators from skin-resident cells. Pruritides are not a formal chemical class; rather, they constitute a mixed set of endogenous mediators and exogenous compounds that produce pruritus.

Mechanisms of action for pruritides vary. Many engage cutaneous C-fiber nociceptors through receptors such as histamine receptors (H1, H4), protease-activated receptors (PAR-2/4), and ion channels including TRPV1 and TRPA1. While histamine-dependent itch accounts for a subset of pruritides, histamine-independent pathways also play a major role, involving cytokines (for example IL-31) and mediators such as leukotrienes, serotonin, endothelin-1, and various proteases that sensitize nerve endings.

Sources and examples. Endogenous pruritides include histamine released from mast cells during allergic reactions and cytokines such as IL-31 produced by immune cells. Exogenous pruritides comprise plant-derived irritants (such as certain alkaloids and urushiol), venom components, some drugs, and environmental allergens that trigger itch responses.

Clinical relevance and research. The use of the term pruritide varies, and clinicians more commonly refer to pruritogens or itch mediators. Research on pruritides aims to map itch pathways and develop antipruritic therapies, targeting both histaminergic and non-histaminergic mechanisms, including receptor antagonists and ion-channel modulators. See also pruritus, pruritogen, and nociception.