This study examined the efficacy of ceramide-containing moisturizing bath products and ceramide-containing shampoos in dogs with atopic dermatitis through a randomized, single-blind comparative trial. The subjects were dogs with atopic dermatitis receiving a systemic administration of oclacitinib at 0.4–0.6 mg/kg once a day, and a total of 20 cases were randomly assigned to either the bath product group or the shampoo group. Bathing or shampooing was conducted twice a week for 4 weeks. The canine atopic dermatitis extent and severity index (CADESI-04) and pruritus visual analogue scale (PVAS) were assessed every two weeks in both groups. In 11 cases, the dose of oclacitinib was tapered starting from the second week, and the medication score (MS) was evaluated at the end of the trial. In 6 dogs from each group, the transepidermal water loss (TEWL) in the axilla, inguinal region, and pinnae was measured every two weeks. After the trial, significant improvements in CADESI-04 and PVAS were seen at 2 and 4 weeks in both groups (p<0.05). TEWL significantly improved in the bath product group’s inguinal region and the shampoo group’s axilla at 4 weeks, and in the shampoo group’s inguinal region at both 2 and 4 weeks (p<0.05). The total oclacitinib dose significantly decreased from 2 to 4 weeks (p<0.05), without worsening symptoms. The results of this study indicate that both ceramide-containing moisturizing bath products and shampoos may serve as useful adjunctive therapies for canine atopic dermatitis.

Collagen density in the abdominal skin of 32 dogs was visualized using an ultrasound imaging system used to investigate age-related changes in humans. The mean (median) collagen score of the dogs was 65.925 (65.8), and when the dogs were divided into three groups according to age (0–5 years, 6–12 years, and 13–17 years); no significant differences were found among the groups' median values (p>0.05). The possibility of visualizing collagen density in dog skin using ultrasound imaging is promising, and in this study, unlike humans, an age-related decrease in skin collagen was not evident in dogs.