Pharmacological control of itch cholinergic constituent in atopic dermatitis patients

Abstract

The aim of the study. To study pharmacological efficacy of antihistamines with both M-holino- and H-histaminoreceptors activity and with electoral effect on H1- histaminoreceptors on acetylholine - induced itch in atopic dermatitis (AD) patients. Materials and methods. 60 AD patients were investigated. All patients were divided on 2 groups. The 1-st group took chloropiramine hydrochloride 25 mg three times daily for 7 days. The 2-d group took cetirizine hydrochloride 10 mg once daily for 7 days. Microcirculation in two symmetric sites of the intact skin area of forearms was estimated with laser doppler flowmetry in standard conditions. Then 20 µIΛ of 0,5 M acetylholine (ACH) solution was injected intracutaneously into a back surface of the left forearm (for control the same volume of 0,9% NaCl solution was injected into a symmetric point of the right forearm) and during 20 minutes the skin reaction was measured with microcirculation index (1sm proximately ACH injection) and local sensation was estimated by means of visual analog scale before treatment, on 7th day of antihistamines treatment and 3d day after treatment. Also index SCORAD, intensity of itch, facts of diary self-control was estimated before treatment, on 7th day of antihistamines treatment and 3d day after treatment. Results. AD patients felt an itch in the ACH injection site before the beginning of antihistamines administration. All patients from the lgroup and patients with mild and moderate dermatitis on the 3-rd day after antihistamines treatment felt ACH-induced tingling and burning. All patients from the 2 group and severe AD patients from the 1 group felt a weak itch in the ACH injection site at the 7-th day of administration and at the 3-rd day after antihistamines treatment completion. Intracutaneous ACH-injection increased cutaneous blood-flux, weal and flare reactions in mild and moderate AD; in severe AD there was no increasing of cutaneous blood-flux, weal and flare reactions, but a significant increased intensity and duration of itch. During chloropiramine and cetirizine treatment the recovery of normal reaction of skin was established. Chloropiramine demonstrated long-term reduction of itch at the 3-d day after the treatment completion as compared with cetirizine. Conclusions: Administration of lgeneration antihistamines with anthicholinergic activity in complex therapy of AD patients is more preferable to reduce itch.