Adverse Reactions to Yeast Beta-Glucan Supplementation in Two Dogs with Inflammatory Bowel Disease

Beta-glucans are immunomodulatory compounds known to act as adjuvants in the beneficial regulation of various allergic conditions, particularly atopic dermatitis, as well as in the modulation of dysbiosis in patients with chronic gastrointestinal disorders. However, certain underlying conditions, such as inflammatory bowel disease (IBD) and the associated loss of oral tolerance, may alter the expected outcomes of supplementation and lead to dysregulated immune responses. This study reports cases of cutaneous allergic reactions in dogs with IBD following the oral administration of yeast-derived beta-glucan. Two dogs with controlled IBD received 9.13 ± 1.14 mg/kg of beta-glucan in a double-blind study designed to investigate its effects on the intestinal microbiota in IBD. Both animals were withdrawn from the study due to adverse effects, including cutaneous allergic manifestations and intense pruritus. These findings suggest that patients with impaired oral tolerance may develop cutaneous reactions following the ingestion of yeast-derived prebiotics.