Itch historical perspective
|
Itch Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Itch historical perspective On the Web |
|
American Roentgen Ray Society Images of Itch historical perspective |
|
Risk calculators and risk factors for Itch historical perspective |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Ogechukwu Hannah Nnabude, MD
Overview
Until recent times, sensations of itch were considered to be largely the same as those for pain. Currently, pruritus is considered to be an autonomous, pain-independent sensation.
Etymology
- Itch, also known medically as pruritus, The first documented definition of itch was given by the German physician Samuel Hafenreffer as an “unpleasant sensation that elicits the desire or reflex to scratch” about 350 years ago.[1] In recent years, pruritus has been determined to be an autonomous, pain-independent sensation. [2]
- Pruritus is a frequently misspelled word, often misspelled as "pruritis" [3]
- Hyperknesis, a term introduced by LaMotte, is defined as “a pathological sensory state in which the itch threshold is lowered and/or a stimulus that does not normally evoke itch, but does now, and/or there is enhanced itch to normal itch‐provoking stimuli” [4]. It is derived from the Greek word knesis which means itching. Alloknesis is defined as “a type of hyperknesis in which certain stimuli that normally do not evoke itch, for example gently warming or stroking the skin, do so” [5]
- Atmoknesis (or aerogenic pruritus), a term that is defined as itching that is brought about, or seemingly brought about, by air touching the skin, as would be expected when a person undresses. It is feature often noted in psoriasis and atopic dermatitis patients [6].
Landmark Discoveries
- Historically, the sensations of itch and pain have not been considered to be independent of each other until recently where it was found that itch has several features in common with pain but exhibits notable differences.[7] Pruritic stimuli mostly create the same reactions as noxious stimuli in experimental animals. As a result, it is difficult to study the physiologic mechanisms of itch in animal models as they lack the ability to discern the differences between both stimuli. Therefore human studies have provided most of the information regarding the processing of pruritic stimuli. [8] [9] [10]. Bell et al. demonstrated that histamine promotes the influx of calcium at the axon terminals of the spinal cord neurons via a transient receptor vanilloid 1 (TRPV1) receptor activation and then, through the promotion of a series of intracellular signal activation, eventually lead to the generation of itching sensation [8]. However, the current consensus is that there are other chemical mediators that are highly involved in the promotion of pruritus.
References
- ↑ Han L, Dong X (2014). "Itch mechanisms and circuits". Annu Rev Biophys. 43: 331–55. doi:10.1146/annurev-biophys-051013-022826. PMC 4081479. PMID 24819620.
- ↑ Metz M, Grundmann S, Ständer S (2011). "Pruritus: an overview of current concepts". Vet Dermatol. 22 (2): 121–31. doi:10.1111/j.1365-3164.2010.00945.x. PMID 21251097.
- ↑ Fleischer AB (2016). "Increasing Incidence within PubMed of the Use of the Misspelling "Pruritis" (sic) Instead of "Pruritus" for Itch". Acta Derm Venereol. 96 (6): 826–7. doi:10.2340/00015555-2393. PMID 26934962.
- ↑ Keele CA, Armstrong D. Substances producing pain and itch. London: E Arnold, 1964: 288– 304.
- ↑ LaMotte RA. Subpopulations of “nocifensor neurons” contributing to pain and allodynia, itch, and alloknesis. Am Pain Soc J 1992: 1: 115– 126.
- ↑ Bernhard JD (1989). "Nonrashes. 5. Atmoknesis: pruritus provoked by contact with air". Cutis. 44 (2): 143–4. PMID 2667901.
- ↑ Twycross, R., Greaves, M.W., Handwerker, H., Jones, E.A., Libretto, S.E., Szepietowski, J.C., Zylicz, Z. (2003). Itch: scratching more than the surface. Q J Med, 96, 7-26.
- ↑ 8.0 8.1 Bell JK, McQueen DS, Rees JL (2004) Involvement of histamine H4 and H1 receptors in scratching induced by histamine receptor agonists in Balb C mice. Br J Pharmacol 142 (2):374-80. DOI:10.1038/sj.bjp.0705754 PMID: 15066908
- ↑ Shim WS, Oh U (2008). "Histamine-induced itch and its relationship with pain". Mol Pain. 4: 29. doi:10.1186/1744-8069-4-29. PMC 2519061. PMID 18667087.
- ↑ Strasser A, Wittmann HJ, Buschauer A, Schneider EH, Seifert R (2013). "Species-dependent activities of G-protein-coupled receptor ligands: lessons from histamine receptor orthologs". Trends Pharmacol Sci. 34 (1): 13–32. doi:10.1016/j.tips.2012.10.004. PMID 23228711.