An 8-year-old male neutered Scottish Fold, whose pruritic dermatitis treated with cyclosporine (CyA), showed chronic gastrointestinal symptoms. Serum chemistry showed a decrease in the A/G ratio and an elevation in the anti-feline coronavirus (FCoV) antibody titer. Based on the test results, FCoV infection due to immunodeficiency was suspected, therefore CyA was withdrawn. As a replacement, oclacitinib was administered. Pruritis was controlled by oclacitinib administration, and then improvement of gastrointestinal symptoms and decrease in the anti-FCoV antibody titer was also observed. However, in a year and a half, the cat was diagnosed with kidney lymphoma, thus oclacitinib administration was withdrawn. The result of this case suggest that oclacitinib administration could be an effective treatment of pruritic dermatitis in cats, but clinicians need to pay close attention to immunosuppression when using high dosages.