Faecal Microbiota Transplantation Reduces Lesion Severity and Medication Use in Canine Atopic Dermatitis: A...

Faecal microbiota transplantation (FMT) is an established therapy for gastrointestinal disease, yet its role in canine atopic dermatitis (cAD) remains unclear.

We hypothesised that adjunctive FMT improves clinical severity and reduces symptomatic medication use in dogs with cAD. The objective was to evaluate efficacy and safety versus placebo.

Forty-six client-owned dogs with naturally occurring cAD were enrolled from a referral hospital population; 40 completed the study (FMT n = 20, placebo n = 20).

Prospective, randomised, placebo-controlled, double-blinded clinical trial. Dogs received daily oral lyophilised FMT capsules for 90 days plus three monthly rectal FMT administrations (Day [D]0, D30, D60) or placebo capsules with sham handling. Concomitant symptomatic therapies were permitted. Outcomes included Canine Atopic Dermatitis Extent and Severity Index, fourth iteration (CADESI-04), pruritus Visual Analog Scale (PVAS), Medication Score (D0-90) and Owner Global Assessment of Treatment Efficacy (OGATE, D90).

CADESI-04 scores were lower with FMT at month (M) 2 (7 ± 6 vs. 16 ± 12; p = 0.006) and month 3 (8 ± 6 vs. 15 ± 12; p = 0.020). Sustained responders (≥ 50% CADESI-04 improvement at M2 and M3) were more frequent with FMT (35% vs. 5%; p = 0.044). In the FMT group, the medication scores were lower at M2 (16 ± 10 vs. 23 ± 11; p = 0.033) and M3 (13 ± 10 vs. 24 ± 15; p = 0.007) compared to placebo. PVAS decreased in both groups without between-group differences. OGATE favoured FMT (p = 0.028). FMT was well tolerated.

Adjunctive FMT reduced lesion severity and medication requirements, supporting its use as a safe microbiome-based add-on therapy in cAD.