Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033774 (pruritus)
 14,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anorectal symptoms and complaints are common and may be caused by a wide spectrum of conditions. Although most conditions are benign and may be successfully treated by primary care practitioners, a high index of suspicion for colorectal cancer should be maintained, and all patients should be appropriately investigated. Inspection, palpation and anoscopic examination using an Ive's slotted anoscope provide adequate initial assessment. Pruritus ani usually represents a self-perpetuating itch-scratch cycle and is uncommonly due to infection. The history, as well as the physical examination, can distinguish anal pain due to hemorrhoids, fissure, abscess, cancer or proctalgia fugax. The most frequent causes of rectal bleeding are hemorrhoids, fissures and polyps. Diagnoses associated with difficulty in passing stool can range from constipation to fecal incontinence.
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PMID:Common anorectal conditions: Part I. Symptoms and complaints. 1143 Apr 54

Scratching behavior is used to assess itch sensation in animals, but few studies have addressed the relative scratch-inducing capacity of different algesic and pruritic chemicals. Furthermore, central neural mechanisms underlying itch are not well understood. We used electrophysiological and behavioral methods to investigate the ability of several irritant chemicals to excite neurons in the superficial dorsal horn, as well as to elicit scratching, in rats. In anesthetized rats, single neurons in the superficial lumbar dorsal horn, identified by their responsiveness to intracutaneous (ic) histamine, were classified as wide dynamic range (WDR) or nociceptive-specific (NS). Serotonin (5-HT) given ic to the paw excited most (88%) WDR and NS neurons over a prolonged time course (often up to 40 min). 5-HT-evoked responses exhibited significant tachyphylaxis. Most neurons also gave shorter-duration responses to ic capsaicin (92%) and mustard oil (71%). In separate behavioral experiments, significant dose-related hind limb scratching directed at the ic injection site in the back of the neck was elicited by 5-HT over a time course similar to that of evoked neuronal firing. A second 5-HT injection made 40 min later at the same site elicited significantly less scratching. Formalin also elicited scratching that was not dose-related and less than that evoked by 5-HT. 5-HT and Formalin also evoked head or whole-body shakes that were significantly correlated with scratching. Neither histamine, capsaicin, nor vehicle controls elicited significant scratching or shaking. In rats, 5-HT appears to be more pruritogenic than histamine as assessed by scratching and shaking behavior, and excites superficial dorsal horn neurons over a behaviorally relevant time course. However, because most neurons additionally responded to pain-producing stimuli, they are not itch-specific. They might nonetheless contribute to neural pathways that distinguish between pain and itch based on some neural mechanism such as frequency coding.
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PMID:Responses of superficial dorsal horn neurons to intradermal serotonin and other irritants: comparison with scratching behavior. 1187 2

Intradermal injection of substance P elicits an itch sensation in human subjects and an itch-associated response in mice. The substance P-induced itch-associated response in mice is not inhibited by antihistamine. Therefore, the mechanisms of substance P-induced itch-associated response are unclear. In this study, we demonstrated one of the mechanisms. Substance P induces an arachidonate cascade to produce prostaglandins and leukotriene. In this study we considered whether arachidonate metabolites are involved in the substance P-induced itch-associated response. A phospholipase A(2) inhibitor arachidoryltrifluoromethyl ketone inhibited the substance P-induced itch-associated response in mice. Pre treatment with the glucocorticoids betamethasone and dexamethasone also produced inhibition of the substance P-induced itch-associated response in mice as well as humans. The 5-lipoxygenase inhibitor zileuton, but not the cyclooxygenase inhibitors indomethacin and diclofenac, suppressed substance P-induced itch-associated response. The leukotriene B(4) receptor antagonist 5-[2-(2-carboxyethyl)-3-[6-(4-methoxyphenyl)-5E-hexenyl]oxyphenoxy]valeric acid produced inhibition, whereas pranlukast (leukotriene C(4)/D(4)/E(4) receptor antagonist) and 5(Z)-7-[1S,2S, 3S,5R-3-(trans-b-styren)sulfonamido-6,6-dimethylbi cyclo(3,1,1)hept-2-yl]-5-heptenoic acid (EP(1) receptor antagonist) were without effect. Furthermore, when the production of leukotriene B(4) and prostaglandin E(2) was measured in skin injected with substance P and in mouse keratinocytes applied with substance P, the level of both products increased. As leukotriene B(4), but not prostaglandin E(2), also induces the itch-associated response in mice, these results suggest that leukotriene B(4) and keratinocytes, cutaneous cells which produced leukotriene B(4), play an important role in substance P-induced itch-scratch response in mice. Leukotriene B(4) receptor antagonist and 5-lipoxygenase inhibitor may be novel antipruritic drugs.
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PMID:Involvement of leukotriene B(4) in substance P-induced itch-associated response in mice. 1188 31

Managing atopic eczema represents one of the most challenging aspects of dermatology nursing, especially in children. A main contributing factor to the difficulty in management is the unrelenting pruritus experienced by sufferers. A practice model for behavior modification can be an effective nursing strategy in the management of pruritus and scratch associated with atopic eczema.
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PMID:Behavior modification: a nursing approach for young children with atopic eczema. 1191 95

Itch is a major symptom of skin disease and is poorly understood, in part due to the lack of adequate small animal models. We show, using iontophoresis of histamine and capsaicin, that it is possible to induce scratching behaviour in both guinea pig and mouse. Use of iontophoresis may obviate the problems of induction of pain as well as itch when injection is used. The behavioural response to capsaicin, however, differs from that seen with histamine, raising the possibility that the use of scratch counts as a method of measuring itch severity needs to be set in the context of other responses. Naloxone partly inhibits scratching in mouse and guinea pig due to histamine. We also show that contact sensitization with 2-4 dinitrochlorobenzene (DNCB) can be used as a simple assay for chronic itch allowing study of scratching over at least a 15-h period. The characteristics of scratching (but not the time course) induced with DNCB are similar to those seen with histamine.
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PMID:Production of acute and chronic itch with histamine and contact sensitizers in the mouse and guinea pig. 1219 Sep 36

There is a strong need for antipruritic substances for treating itch in clinical dermatology. In one recent human study, topically applied acetylsalicylic acid has been described to rapidly decrease histamine-induced itch. We have established a model for periferally elicited pruritus by injecting serotonin into the rostral back area (neck) in rats. Using this model, we aimed to investigate the antipruritic potential of four different salicylic compounds, which all possess different skin penetration characteristics. Eighteen rats were studied for 6 weeks. Prior to serotonin injections (2 mg/ml, 50 micro l), 10 micro l of test substances was applied to a circular area 18 mm in diameter. The four substances were salicylic acid, butyl salicylate, diethylamine salicylate and salicylamide, all solubilized in dimethyl isosorbide to a concentration of 5% w/w. Diethylamine salicylate and salicylamide were previously shown to be slowly absorbed through rat skin in contrast to salicylic acid and butyl salicylate. After serotonin injections, scratching was monitored by video recording for 1.5 h. Compared with the vehicle, a lower number of scratch sequences were seen when diethylamine salicylate (P < 0.001) and salicylamide (P = 0.005) had been applied. The numbers of scratch sequences were lower with diethylamine salicylate and salicylamide than with the vehicle throughout the 1.5-h study period. We conclude that topical application of diethylamine salicylate and salicylamide could suppress serotonin-induced scratching in rats. The antipruritic effect seems to be related to the slow drug release of the two substances. The results may be clinically relevant as serotonin induces itch in humans.
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PMID:The effect of topically applied salicylic compounds on serotonin-induced scratching behaviour in hairless rats. 1219 Sep 47

Experimental scratching in animals has hitherto been provoked by substances injected into the skin or central nervous system. We aimed to investigate if spontaneous scratching in the rat can be reduced by sedatives and antipruritics, and to assess if spontaneous scratching is elicited from the skin or the central nervous system. It may also be a complex behaviour related to the rat species, different from clinical itch. Eight male hairless rats were studied for 6 weeks. The animals were recorded on videotape in the middle of the day and at night, and the scratching activity was counted. The following substances were tested sequentially: midazolam, mepyramine, a eutectic mixture of lignocaine and prilocaine (EMLA, betamethasone dipropionate and a vehicle. On days 1-3 of each sequence, the test material was applied to a 42-cm(2) area on the rostral part of the back. Subsequent treatment of the whole body was made on day 4. Midazolam was injected intraperitoneally from day 1 to day 4. After 4 days of treatment, there was a wash-out phase of 3 days until the next sequence. We found a positive correlation between minutes awake and number of scratch episodes. Spontaneous scratching was lower after mepyramine on day 4 (p = 0.046) and after midazolam injections on days 1-3 (p = 0.009) and day 4 (p = 0.003). The local anaesthetic, EMLA, did not significantly influence spontaneous scratching. In conclusion, only the drugs with sedative properties suppressed spontaneous scratching, which is probably a cerebral phenomenon or otherwise explained general behaviour, rather than a reaction to skin stimuli. Thus, for testing of topically applied antipruritics, spontaneous scratching cannot be used as an animal model. Furthermore, evaluation of provocative scratching should eliminate/exclude spontaneous scratching.
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PMID:Suppression of spontaneous scratching in hairless rats by sedatives but not by antipruritics. 1221 83

We examined the scratch (itch) inducing effect of 1,8-cineole (cineole), a monoterpene oxide present in many plant essential oils and the possible role of mast cells in the response. Subcutaneous injection of cineole (10, 20 and 40 microl/site) or the mast cell degranulating agent, compound 48/80 (25, 50 and 100 microg/site) into the rostral back of mice induced a scratching behavior. This response of cineole as well as that of 48/80 was markedly suppressed in mice subjected to mast cell desensitization by repeated injections of 48/80. The cineole-induced scratching was also significantly diminished in animals pretreated with diphenhydramine, the histamine H1-receptor antagonist or cyproheptadine, the dual histamine/serotonin-receptor antagonist. Furthermore, the scratch-inducing effect of cineole was greatly reduced in mice that received the opioid antagonist naloxone or the selective adenosine A1-receptor agonist, N6-cyclopentyladenosine (CPA), but not the more selective adenosine A2-receptor agonist, 5'-N-ethylcarboxamidoadenosine (NECA). The data suggest a likely role for mast cells in cineole-induced scratching behavior of mice, possibly involving adenosinergic and opioidergic mechanisms.
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PMID:Possible role of mast cells in cineole-induced scratching behavior in mice. 1238 8

Vulvar cancer was reported in 3,200 women in 1998, resulting in 800 deaths. Recent evidence suggests that vulvar cancer comprises two separate diseases. The first type may develop from vulvar intraepithelial neoplasia caused by human papillomavirus infection and is increasing in prevalence among young women. The second type, which more often afflicts older women, may develop from vulvar non-neoplastic epithelial disorders as a result of chronic inflammation (the itch-scratch-lichen sclerosus hypothesis). Although vulvar cancer is relatively uncommon, early detection remains crucial given its significant impact on sexuality. Diagnosis is based on histology; therefore, any suspicious lesions of the vulva must be biopsied. Excisional or punch biopsy can be performed in the physician's office. Clinicians must closely monitor suspicious lesions because delayed biopsy and diagnosis are common. Once diagnosed, vulvar cancer is staged using the TNM classification system. Treatment is surgical resection, with the goal being complete removal of the tumor. There has been a recent trend toward more conservative surgery to decrease psychosexual complications.
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PMID:Vulvar cancer. 1238 39

Lichenification is characterized clinically by thickening of areas of skin as a result of the itch-scratch cycle and therefore is seen in conditions associated with chronic pruritus. The characteristic feature of giant lichenification is the occurrence of tumour-like growths with a warty cribriform surface. We describe a renal transplant patient presenting with giant lichenification of the scalp following an attack of herpes zoster at the same site. Chronic pruritus following scalp dysaethesia secondary to herpes zoster was considered the most likely explanation for the occurrence of these lesions.
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PMID:Giant lichenification of the scalp. 1278 Jul 6


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