A pilot trial on the effect of Cyclosporin A on intradermal skin test reactions in dogs with atopic dermatitis

Abstract

The purpose of this study was to determine if Cyclosporin A, given at a dose of 5 mg kg−1 per day for 42 days, negatively influenced intradermal skin test results in dogs with atopic dermatitis. Six mixed‐breed dogs of varying ages and sexes with a clinical diagnosis of atopic dermatitis were included in this study. All dogs were intradermally skin tested (IDT) with 61 allergens from varying groups, grass pollens, weed pollens, tree pollens, moulds, insects and dust mites. IDT reactions were recorded as absent, weak, moderate or strong reactions. All dogs showed several strong reactions in the initial IDT. On days 0 to 42, the dogs received 5 mg kg −1 per day of Cyclosporin A. On day 42, all dogs showed a marked reduction in pruritus. A second IDT was performed and the results of both tests compared. The χ2‐test was used to statistically analyse changes between pre‐ and post‐treatment reactions for each of the allergen groups. There were no mould reactions recorded and this group was discarded from analysis. When all reactions were used in analysis, Cyclosporin A tended to significantly reduce the number of IDT reactions. However, when only moderate and strong reactions were considered (weak reactions excluded) there were no significant differences between pre‐ and post‐treatment results for the other allergen groups. Cyclosporin A at a dose of 5 mg kg−1 per day for 42 days controlled pruritus, but did not significantly alter moderate and strong intradermal skin test reactions in the six dogs tested. This suggests that Cyclosporin A, at this dose, did not prevent mast cell degranulation. Funded by Novartis Animal Health, Australia.