Lower faecal IgA linked to canine atopic dermatitis, study shows

2 September 2026

Faecal immunoglobulin A (IgA) concentration is associated with canine atopic dermatitis, with a significantly lower mean ranked faecal IgA seen in atopic than in healthy dogs, according to new research.

Canine atopic dermatitis (CAD) is a common, genetically disposed, lifelong condition that requires ongoing management to prevent relapses. Understanding the aetiopathogenesis of CAD, and the interaction between the skin, the immune system, the microbiome, and the environment, is important for refining treatment strategies.

A new study, funded by BSAVA PetSavers and published in the Journal of Small Animal Practice, characterised immunoglobulin A (IgA) levels in dogs presenting to veterinary practice with CAD.

Faecal and saliva samples were collected from 32 atopic dogs and 36 control dogs 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.

The faecal IgA concentration was significantly lower in atopic dogs – ranging from 0.05 to 5.28 g/L – than in control dogs – ranging from 0.014 to 10.27 g/L (p=0.03). In contrast, salivary IgA concentrations did not differ significantly between atopic and healthy groups. Faecal and salivary IgA concentrations were not correlated (i.e. dogs with low faecal IgA did not always have low salivary IgA). Faecal and salivary IgA concentrations were not associated with age or breed.

Dr Francesca Soutter, corresponding author of the study, said: “This work reveals a potential role for gastrointestinal mucosal immunity in CAD, that may go beyond food allergy. We hope to explore and understand this association through further research to provide improved treatment and prevention strategies”.

The researchers recommend that future work should be carried out on larger cohorts and on high-risk breeds from birth through to adulthood, to increase understanding of the role of IgA in the development of gut tolerance versus immune dysregulation.

Read the paper in the Journal of Small Animal Practice: https://onlinelibrary.wiley.com/doi/10.1111/jsap.70184.