Nedocromil sodium inhibits histamine‐induced itch and flare in human skin

Abstract

This study was designed to test the hypothesis that nedocromil sodium inhibits sensory nerve function to reduce¯are and itch in human skin. Nedocromil sodium (2%) or water (control) was introduced into the volar forearm skin of eight non-atopic volunteers by iontophoresis (8 mC) and histamine (20 ml of 1 mM and 300 nM) injected intradermally 10 min later at the same site. Itch was assessed on a visual analogue scale every 20 s for 5 min. Weal and¯are areas and mean blood¯ux within the¯are were assessed by scanning laser Doppler imaging at 10 min. The results showed that nedocromil sodium reduced itch scores, totalled over 5 min, by *74.0% (P50.005) and¯are areas by *65% (P50.03). Neither weal areas nor blood¯ux within were reduced. These data demonstrate that nedocromil sodium is e ective in reducing neurogenic itch and¯are in the skin. We suggest that its mechanism of action is modulation of sensory neurone activation or conduction in the skin.

Population pharmacokinetic/pharmacodynamic modeling of histamine response measured by histamine iontophoresis laser Doppler

“…HILD method has been used to monitor the histamine-induced local blood flow modification after antihistamine treatment [9, 10]. However, interpretation of such measurements has traditionally been simple and descriptive.…”

Topical sodium cromoglicate relieves allergen- and histamine-induced dermal pruritus

“…Finally, a study using nedocromil sodium, a chromone compound similar to SCG, found a substantial reduction of both itch and flare but neither weal nor increased blood flux, the latter being the equivalent of skin temperature in our study. These data led the authors to conclude that the mechanism for this effect was not inhibition of mast cell degranulation but instead an inhibition of sensory nerve activation or transmission 13 …”

Interactions between eotaxin, histamine and mast cells in early microvascular events associated with eosinophil recruitment to the site of allergic skin reactions in humans

“…Thus the concentration of histamine injected may have been too small to initiate eosinophil accumulation. We did not inject higher concentrations as the dose used had previously been demonstrated to be safe for intradermal injection into humans [13]. In fact only one of three volunteers developed a weal and flare following histamine injection at this concentration.…”