Edinburgh Team Links Faecal IgA to Canine Atopic Dermatitis

Researchers at the University of Edinburgh have found significantly lower faecal immunoglobulin A (IgA) concentrations in dogs with canine atopic dermatitis (CAD) compared with healthy controls. Published in the Journal of Small Animal Practice on 3 September 2026 and funded by BSAVA PetSavers, the study points to a potential role for gastrointestinal mucosal immunity in CAD pathogenesis beyond food allergy alone, extending the growing gut-skin axis research theme into companion animal dermatology.

The team collected faecal and saliva samples from 32 atopic dogs and 36 healthy control dogs recruited through the first opinion and dermatology referral service at the Royal (Dick) School of Veterinary Studies Hospital for Small Animals at the University of Edinburgh. IgA concentrations were measured using a commercial dog IgA ELISA kit. Faecal IgA concentrations were significantly lower in atopic dogs (0.05 to 5.28 g/L) than in control dogs (0.014 to 10.27 g/L; p=0.03). Salivary IgA concentrations, by contrast, did not differ significantly between the atopic and healthy groups. Faecal and salivary IgA concentrations were not correlated, and neither was associated with age or breed.

Corresponding author Dr Francesca Soutter positioned the findings as revealing a potential role for gastrointestinal mucosal immunity in CAD that may extend beyond established food allergy mechanisms. The researchers recommend future work in larger cohorts and in high-risk breeds followed longitudinally from birth to adulthood, to clarify the role of IgA in gut tolerance versus immune dysregulation. The findings tie into a broader pharmacology and nutrition research theme investigating gut-skin axis interactions across companion animal dermatology, with substantial commercial implications for premium companion animal microbiome-focused nutrition and dermatology-adjacent therapeutic categories.

The commercial signal is a growing gut-skin axis research theme with substantial potential to reshape companion animal dermatology treatment approaches beyond current standard-of-care. Microbiome-focused diagnostics and nutritional interventions increasingly complement established immunology-focused therapeutics. Expect Zoetis (Apoquel, Cytopoint), Boehringer Ingelheim, Elanco, Nestlé Purina, Mars Petcare (Royal Canin) and Hill’s Pet Nutrition to sharpen positioning around microbiome-informed dermatology through 2027.

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