Atopic dermatitis (AD) is very common and sometimes the treatment would be challenged in dogs. Cyclosporine A (CsA) has been used in canine AD for its tolerance and efficacy compared to steroids. This study aimed to investigate safety, efficacy, and mechanism of CsA in canine AD.
Blood works and urinalysis for safety verification every 4 weeks and Canine Atopic Dermatitis Extent and Severity Index (CADESI)-03, pruritus, overall coat condition, and scaling scores for clinical evaluation of the atopic dogs (n=7) were performed by every 2 weeks for 8 weeks. In addition, systemic total IgE, Th1/Th2 cytokines, mast cell, CD3-positive T cells in the skin biopsy samples were evaluated in atopic dogs by ELISA, semi-quantative PCR.
Blood works and urinalysis every 4 weeks showed no remarkable. CADESI score reduced significantly (P=0.0034, paired t-test) after 8 weeks, pruritus and scaling scores were improved significantly over times compared to base line. But overall coat condition showed no significant changes. Total serum IgE showed reduction pattern after 8 weeks, but there was not significant compared to the base line.
In mRNA level, IL-2 and TNF-α related to Th1 and IL-4 and IL-10 related to Th2 cytokines showed suppressive tendencies, but no significant difference were remarked after 8 weeks in the skin tissue. In histopathology, the inflammatory changes and mast cell counts showed significantly improved after 8 weeks.
In conclusion, CsA has efficacy and safety in atopic dogs, suppression of Th1 and Th2 cytokines were suspected mechanism in this study.

Key words: Atopic dermatitis, CADESI, Cyclosporine, Dogs, Mechanism