Pruritus
Basics
Description
Description
- Unpleasant yet common sensation that provokes a desire to scratch
- Chronic if persisting for more than 6 wk (incidence increases with age)
- Generally accepted to be mediated by unmyelinated C-fibers in upper portion of dermis (distinct from those for pain):
- Transmitted to dorsal horn of spinal cord
- Via spinothalamic tract to cerebral cortex
- Peripheral mediators (e.g., histamine and peptides such as substance P that release histamine) stimulate C-fibers and induce itching
- Prostaglandins (PGE2, PGH2) lower threshold to pruritus
- Opiates cause pruritus by acting on central receptors
- No single pharmacologic agent effectively treats all causes of pruritus
- “Itch–scratch–itch” cycle:
- Itching triggers scratching
- Scratching damages skin and stimulates nerve endings, thereby producing even greater itching
Etiology
Etiology
- Dermatologic causes
- Neurologic causes: Due to CNS or PNS lesions
- Psychogenic causes
- Systemic causes
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Citation
Schaider, Jeffrey J., et al., editors. "Pruritus." 5-Minute Emergency Consult, 6th ed., Lippincott Williams & Wilkins, 2020. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307147/5.0/Pruritus.
Pruritus. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307147/5.0/Pruritus. Accessed November 14, 2024.
Pruritus. (2020). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (6th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307147/5.0/Pruritus
Pruritus [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. [cited 2024 November 14]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307147/5.0/Pruritus.
* Article titles in AMA citation format should be in sentence-case
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BT - 5-Minute Emergency Consult
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