A Randomized Controlled Trial to Evaluate the Impact of a Novel Probiotic and Nutraceutical Supplement on Pruritic Dermatitis and the Gut Microbiota in Privately Owned Dogs

Simple Summary: Given that skin allergies and pruritic dermatitis are highly prevalent in dogs, with a lack of reliable treatment methods, a dietary supplement containing a blend of probiotics, prebiotics, vitamins, nutrients and a yeast-derived postbiotic was developed with the potential to promote symptom reduction through dermatological, immune, and gastrointestinal support. To assess the impact of this supplement on clinical signs of allergy and the gut microbiome, which may influence such symptoms, in companion dogs with pruritic dermatitis, a 10-week trial was conducted. The supplement supported faster improvements and resolution of pruritus, with differences seen compared to a placebo group after 2 weeks. Simultaneously, at the end of the trial, the gut microbiome in treated dogs was enriched with three of the supplemented probiotic species, and unhealthy species were reduced. The enrolled client-owned dogs represented a variety of breeds, ages, and sizes with diverse pruritus severity, which may make the results of this trial more applicable to a larger population of dogs with pruritic dermatitis. Future trials should expand upon the use of dietary supplements with multimodal capabilities for the relief of pruritic dermatitis under stricter cohort definitions. Pruritic dermatitis (PD) is a common presentation of canine allergic skin diseases, with diversity in severity and treatment response due to complex etiopathogenesis. Evidence suggests the gut microbiota (GM) may contribute to the development of canine allergies. A 10-week double-blind randomized controlled trial evaluated a novel probiotic and nutraceutical blend (PNB) on clinical signs of skin allergy, health measures, and the GM of privately owned self-reported pruritic dogs. A total of 105 dogs were enrolled, with 62 included in pruritus and health analysis and 50 in microbiome analysis. The PNB supported greater improvement of owner-assessed clinical signs of PD at week 2 than the placebo (PBO). More dogs that received the PNB shifted to normal pruritus (digital PVAS10-N: <2) by week 4, compared to week 7 for the PBO. While a placebo effect was identified, clinical differences were supported by changes in the GM. The PNB enriched three probiotic bacteria and reduced abundances of species associated with negative effects. The PBO group demonstrated increased abundances of pathogenic species and reduced abundances of several beneficial species. This trial supports the potential of the PNB as a supplemental intervention in the treatment of PD; however, further investigation is warranted, with stricter diagnostic criteria, disease biomarkers and direct veterinary examination.