"The prevalence of canine atopic dermatitis in developed countries has been growing constantly over the last few decades. Genetic predisposition represents only part of the problem, and environmental factors are believed to be an important boost to the rapid rise in atopic dogs.
Although a complete understanding of the gut–skin axis has not yet been achieved, a growing number of studies demonstrate a close relationship between gastrointestinal imbalance and skin diseases."
What do we see? Commonly, rashes and itchy skin.
Not only that, while it often starts seasonally, as time progresses, it becomes year-round, and more severe. Secondary infections, both bacterial and yeast, frequently develop as self-trauma and inflammation makes the skin more vulnerable.
Sources:
Guidi, E.E.A.; Gramenzi, A.; Persico, P.; Di Prinzio, R.; Di Simone, D.; Cornegliani, L. Effects of Feeding a Hypoallergenic Diet with a Nutraceutical on Fecal Dysbiosis Index and Clinical Manifestations of Canine Atopic Dermatitis. Animals 2021, 11, 2985. https://doi.org/
10.3390/ani11102985
Marsella, R.; De Benedetto, A. Atopic Dermatitis in Animals and People: An Update and Comparative Review. Vet. Sci. 2017, 4, 37. https://doi.org/10.3390/vetsci4030037