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)

Itch sensation is reduced by cooling the skin. We tested whether lowering skin temperature attenuates responses of spinal dorsal horn neurons elicited by intracutaneous (i.c.) microinjection of histamine in anesthetized rats. Cooling the skin to 3 degrees C significantly and reproducibly reduced (to a mean of 48%) i.c. histamine-evoked responses in 20 of 24 wide dynamic range-type dorsal horn neurons. Histamine-evoked responses recovered to control levels after rewarming the skin. Assuming that such neurons play a role in signaling itch, depression of their responses during skin cooling may account for the psychophysical observation that skin cooling relieves itch in humans.
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PMID:Skin cooling attenuates rat dorsal horn neuronal responses to intracutaneous histamine. 992 64

Responses to acetylcholine (ACh) and vasoactive intestinal polypeptide (VIP) were investigated in atopic eczema (AE) patients. To elucidate the involvement of histamine to ACh-provoked vasoreactions and sensations, we applied a selective H1-antagonist (cetirizine) 3 h prior to the ACh-administration. Solutions of acetylcholine (ACh, 0.55 M) and vasoactive intestinal polypeptide (VIP, 1.5x 10(-5) M) were injected (10 microl) intracutaneously into the volar forearm of 14 healthy subjects and 14 atopic eczema (AE) patients. The substances were applied as single stimulus as well as in combination. Sensations evoked by the stimulation were recorded using 2 visual analog scales (VAS). Vasoreactions were analyzed with the new technique of computer assisted video image analysis. With this method we measured the dynamics of the flare development and the extension of the final flare size independent of the observer's assessment. In control subjects the development and extension of the final flare size was almost similar, regardless whether ACh and VIP were applied in combination or separately. Compared to healthy controls, after injection of ACh, VIP and the combination of VIP and ACh smaller flare sizes were recorded in AE patients. After VIP was given, the control subjects reported pruritus, which was significantly augmented compared to AE patients. In contrast, controls reported a burning pain after the injection of ACh, whereas AE patients felt predominantly pruritus. Itch sensation after the combined application of VIP and ACh was significantly elevated in AE patients. Consequently, we assume that mediators of sudomotor neurons, i.e., VIP and ACh meet in AE patients apparently sensitized nociceptive primary afferents and induce exaggerated itch, pain and flare responses. When pretreated with the selective H1-antagonist cetirizine before ACh was injected, pain and erythema due to ACh was diminished in healthy controls. In contrast, cetirizine did not influence the size of erythema and the magnitude of sensation in AE patients. We conclude, that the release of histamine is not involved in ACh-induced erythema and pruritus in AE. These data provide evidence that pruritus can be elicited in atopic eczema by a cholinergic, histamine independent mechanism.
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PMID:Administration of acetylcholine and vasoactive intestinal polypeptide to atopic eczema patients. 1020 20

Itch is one of the major symptoms of skin disease although it remains poorly studied. Little is known about its mediators or the neurological processes involved in either the detection of an itch stimulus or the induction of the main response to itch, scratch. This lack of knowledge may be due to the subjective nature of the sensation itself and the related difficulties in quantifying it, and is compounded by the absence of a convincing animal model. Defining itch as that sensation which provokes the desire to scratch provides two approaches to measurement, that of itch itself, and the behavioural response, scratch. The measurement of itch itself traditionally involves the use of questionnaires or visual analogue scale, both of which rely on the dubious assumption that the subject is able to relate their experiences accurately. By contrast experimental induction of itch and measurement of areas of allokinesis around application sites may provide a more reliable and repeatable method of itch quantification. Recent advances in two areas that may prove relevant are discussed: new technological improvements in movement meters and compatible software; and some recently described animal models.
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PMID:Pruritus: more scratch than itch. 1060 57

Capsaicin (CAP) has been demonstrated to be an effective topical inhibitor of cutaneous vasodilatation, pain and pruritus induced by a variety of chemical and physical stimuli. In a previous study, we showed a significantly inhibitory effect of topical CAP treatment on histamine-induced itch and cutaneous vascular reactions in healthy subjects compared to atopic eczema patients. As serotonin is proposed to play a pathophysiological role in some types of pruritus (e.g. uremic and hepatic pruritus) and CAP has been described to be successful in hemodialysis-related pruritus, we investigated the antipruritic effect of topical CAP on serotonin-induced reactions in 10 healthy volunteers in comparison to untreated skin (UPS) and placebo substance (vehicle)-treated skin (VS). On the first day, serotonin iontophoresis was performed in untreated skin. One week later, the treatments started, using either CAP 0.05% liniment or a placebo liniment (vehicle) 3 times daily over a 5-day period. On day 6, serotonin was applied by iontophoresis within the pretreated skin. After another 1-week break, the treatments were performed vice versa on the corresponding infrascapular region. Weal and flare areas were planimetrically evaluated. Itch sensations were documentated by the volunteer on a scale over a 24-min follow-up period. The examination also comprised alloknesis, which stands for induction of perifocal sensations by usually non-itching stimuli. In CAP-treated skin, serotonin-induced wheals were significantly larger post-application compared to non-pretreated skin. Wheals were significantly larger in VS than in UPS. Comparison of serotonin-induced flares in the different study arms did not reveal any significant differences. Itch sensations were not significantly reduced by topical CAP application. The areas of alloknesis were smaller in capsaicin-treated skin compared to VS and UPS, but did not reach significant value. In conclusion, topical CAP application is not effective in serotonin-induced itching in healthy volunteers. Serotonin is most unlikely to play a role in the mechanism of action of CAP.
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PMID:Lack of efficacy of topical capsaicin in serotonin-induced itch. 1065 61

The effect of thalidomide on itch was studied in 11 patients with chronic pruritus from psoriasis, eczema, nodular prurigo, senile pruritus and primary biliary cirrhosis. Itch, assessed subjectively by the patients on a 10 cm line and measured objectively as nocturnal scratch movement, was decreased by thalidomide 200 mg on the 2 nights it was given. There was no improvement in the underlying disorders and it is concluded that thalidomide is a primary antipruritic agent. The patients all became drowsy and it seems likely that, as with most other antipruritic agents, the antipruritic action of thalidomide results from a central depressant effect. The primary antipruritic effect of thalidomide should now be assessed therapeutically.
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PMID:Antipruritic action of thalidomide. 1072 27

The avian schistosomes, Trichobilharzia stagnicolae, T. physellae and Gigantobilharzia sp., that cause Schistosome Dermatitis (Swimmers' Itch) in humans were studied in the laboratory and at Cultus Lake, British Columbia, Canada in relation to the biology and behavior of their intermediate snail hosts, Stagnicola catascopium, Physa sp. and Gyraulus parvus, respectively, and their definite bird hosts. Wind-driven, surface currents were measured. Populations of snails, close to host-bird roosting logs had a very high prevalence of schistosome infections. An experiment that mechanically disturbed the epilithic habitat of the snails using a boat-mounted rototiller or a tractor and rake, eliminated almost all of the snails if the disturbance was done in areas of high snail concentration in shallow areas of the lake during the breeding and early development phase of the snail. It is proposed that the incorporation of snail habitat disturbance into management programs is an effective way to control Schistosome Dermatitis.
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PMID:Ecological factors in schistosome transmission, and an environmentally benign method for controlling snails in a recreational lake with a record of schistosome dermatitis. 1072 12

While histamine is the crucial mediator of pruritus in type 1 allergic reactions, its role in atopic dermatitis (AD) is unclear. In this study, the role of mast cell mediators in protein extravasation and pruritus was evaluated using intradermal microdialysis. The microdialysis capillaries were used to apply the mast cell degranulating substance compound 48/80 (C48/80; 0.05%) or histamine (0.01%) and also to deliver H1-blockers (cetirizine, 200 microg mL-1) in nine AD patients and nine controls. Large pore size membranes (3000 kDa) enabled simultaneous analysis of protein extravasation. Itch sensation was measured psychophysically and weal and flare reaction were evaluated planimetrically. Protein extravasation induced by histamine and C48/80 was significantly reduced in AD patients. Blockade of H1-receptors by cetirizine significantly reduced C48/80-induced protein extravasation in AD patients and controls to an identical level. C48/80-induced pruritus was abolished by cetirizine in controls, whereas pruritus in AD patients was unchanged after H1 blockade. We conclude that mast cell mediators others than histamine are involved in C48/80-induced pruritus in AD patients. Whether the reduced capacity of AD patients to induce protein extravasation is of pathophysiological relevance for pruritus remains to be established.
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PMID:Mast cell mediators other than histamine induce pruritus in atopic dermatitis patients: a dermal microdialysis study. 1084 27

Genetic studies identified Itch, which is a homologous to the E6-associated protein carboxyl terminus (Hect) domain-containing E3 ubiquitin-protein ligase that is disrupted in non-agouti lethal mice or Itchy mice. Itch-deficiency results in abnormal immune responses and constant itching in the skin. Here, Itch was shown to associate with Notch, a protein involved in cell fate decision in many mammalian cell types, including cells in the immune system. Itch binds to the N-terminal portion of the Notch intracellular domain via its WW domains and promotes ubiquitination of Notch through its Hect ubiquitin ligase domain. Thus, Itch may participate in the regulation of immune responses by modifying Notch-mediated signaling.
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PMID:Recognition and ubiquitination of Notch by Itch, a hect-type E3 ubiquitin ligase. 1094 Mar 13

Seventeen patients were included in a clinical open trial of macrolides for treatment of psoriasis vulgaris. PASI scores, itch and ointment scores were used to evaluate their effectiveness. PASI scores dropped from 22.8 to 13.7; this was statistically significant. Itch reduced in 11 out of 13 patients, and the extent of itch reduced significantly by 54% on average. Ointment scores reduced from 44.9 to 34.4, which was also statistically significant. Macrolides are known not only as potent anti-biotics, but also as immunomodulatory agents. These data suggest that macrolides could be used as one of the adjunctive therapies of psoriasis vulgaris, and this study is a first step toward the future evaluation of macrolides in a double blind trial.
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PMID:An open trial of oral macrolide treatment for psoriasis vulgaris. 1098 74

This study was designed to determine whether low doses of intrathecal morphine still result in itching and it evaluates the outcome of a standardized treatment using promethazine and - for intractable itch - naloxone. Patients (n = 143) scheduled for total hip surgery were allocated to four groups (in a double blind manner) with bupivacaine 20 mg in 4 mL but different doses of intrathecal morphine: Group I, 0.025 mg, Group II, 0.05 mg, Group III, 0.1 mg and Group IV, 0.2 mg. The presence or absence of itching was noted every three hours for a 24-h period. When required, standardized treatment was provided. The incidence of itching was: Group I: 14. 3%; Group II: 21.6%; Group III: 48.6%; and, Group IV: 61.7%. Itch was treated by administering promethazine intramuscularly in 2.9% (Group I); 8.1% (Group II); 10.8% (Group III), and 8.9% (Group IV), respectively. Only in group IV there was a single patient who needed naloxone to treat itching. The incidence and severity of itching is a dose-related side-effect in the dose range of 0.025-0.2 mg of intrathecal morphine. Itching still occurs after the low doses of intrathecal morphine, but symptoms vanish after promethazine 25 mg intramuscularly.
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PMID:Itching after intrathecal morphine. Incidence and treatment. 1105 May 19


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