Experimental dermatology
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Experimental dermatology · Dec 2014
Letter Randomized Controlled TrialPolidocanol inhibits cowhage - but not histamine-induced itch in humans.
Polidocanol is a local anaesthetic and antipruritic compound that is used in the treatment of itching skin conditions such as eczema. Its mechanisms of action are largely ill defined. This study has compared the antipruritic efficacy of topical polidocanol in histamine-induced itch and a histamine-independent, cowhage-induced model of pruritus. ⋯ Itch was recorded at 1-min intervals for 30 min on a 100-mm visual analogue scale. Polidocanol significantly reduced the area under the curve for cowhage-induced itch by 58% (P < 0.05), but had no significant effect on histamine-induced itch. This result underlines the importance of histamine-independent itch models in the development of topical antipruritic agents.
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Experimental dermatology · Apr 2001
Randomized Controlled Trial Comparative Study Clinical TrialDoxepin affects acetylcholine induced cutaneous reactions in atopic eczema.
Atopic eczema (AE) is a chronic inflammatory skin disease with strong itching as the prominent symptom. The pathology of itch is still in discussion, but acetylcholine (ACH) seems to be a relevant pruritogenic mediator in AE. Since efficient benefit on pruritus and excoriations has been demonstrated with tricyclic agents, we investigated how the topical treatment with doxepin (5%, Boehringer Standard, Mannheim, Germany), a tricyclic compound with anticholinergic properties, may influence ACH induced itch and cutaneous sensations (erythema, wheal, axonreflex flare). ⋯ The clinical and experimental effectiveness of doxepin as an antipruritic drug has been known for years. However, studies focusing on ACH as a pruritogenic mediator have not been performed. The duration of the doxepin application in our study seems to be appropriate since flare and wheal development were diminished. The reason why doxepin did not develop more antipruritic action compared to the vehicle cream may be due to the fact that the doxepin free cream already possessed an antipruritic action in this experimental study design. This is probably caused by rehydrating and moisturizing effects.
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Experimental dermatology · Feb 1999
Randomized Controlled Trial Comparative Study Clinical TrialAdministration of acetylcholine and vasoactive intestinal polypeptide to atopic eczema patients.
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. ⋯ 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.