Journal Scan: Bad dog? Pruritus may be to blame

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Why they did it

Inspired by studies in human medicine demonstrating a link between pruritic conditions and psychological distress that can lead to mental health issues such as depression and anxiety, researchers from the University of Nottingham’s School of Veterinary Medicine in Leicestershire, United Kingdom, hypothesized that canine atopic dermatitis (AD) could have a similar effect on man’s best friend. Specifically, they wanted to see if dogs with AD would display more problem behaviors that could be the result of the psychological stress brought on by their condition.

What they did

Owners of purebred golden and Labrador retrievers were recruited to participate as part of the Itchy Dog Project, an online study designed to investigate the genetic and environmental causes of AD in these two breeds. Of the total 895 canine participants, 343 had been diagnosed with AD, and the other 552 healthy dogs served as controls. The pets’ owners were blinded to the study’s hypothesis and filled out questionnaires regarding their dog’s skin health (including a measure of pruritus severity) and behavior.

What they found

The researchers found a direct link between itch severity in dogs with AD and problem behaviors such as mounting, chewing, hyperactivity, coprophagia, begging for and stealing food, attention-seeking, excitability, excessive grooming and reduced trainability. The results did not, however, show an association between pruritus and generally anxious or fearful behavior or aggression. Thus, the researchers conclude, “[the] results could indicate that the dogs diagnosed with AD may be experiencing low-level chronic stress as a result of pruritus.”

Why it’s important

While the findings are significant to the welfare and treatment of dogs with AD, as with so many issues in veterinary medicine, the big picture includes pet owners. “Our study clearly showed a relationship between the occurrences of problematic behavior in dogs and chronic itching,” said lead researcher Naomi Harvey, PhD, in a press release about the research. “This can have a knock-on effect and impact the relationship between owner and dog, which means it’s important for owners to know that their dog’s behavioral problems could be due to the itching, rather than the dog themselves.” Because as the study elaborates, “behavioral problems are the main reason given for relinquishing animals to shelters. Combined with the increased financial burden of treating and managing this chronic condition, and reduced quality of life reported by owners of dogs with AD, the problem behaviors shown by pruritic dogs in this study could disproportionately increase their risk of being relinquished by their owners.”

Thus, the findings suggest that AD treatment should include client education aimed at reducing environmental stressors and protecting the human-animal bond. According to Dr. Harvey, this approach could also have an effect on the pruritis itself. “Given the large amount of evidence already available demonstrating the impact of stress in skin barrier function and the increased stress reported by human patients with AD, it is more than plausible that psychological stress experienced by dogs with AD could prolong and exacerbate allergic flares,” she said in the release.

What’s next

Association is not causation, so more research is needed to determine whether pruritus causes stress in dogs with AD or if other factors are to blame. As the researchers conclude, “Given the potential importance of stress in AD development and the implications of the behavioral problems we have found for dog and owner bonds, further studies need to be carried out.”

To read the full study, click here.

Harvey ND, Craigon PJ, Shaw SC, et al. Behavioural differences in dogs with atopic dermatitis suggest stress could be a significant problem associated with chronic pruritus. Animals 2019;9(10):813.

Sarah Mouton Dowdy, a former associate content specialist for dvm360.com, is a freelance writer and editor in Kansas City, Missouri.