Inflammatory Bowel Disease in Patients With Atopic Dermatitis and Allergic Rhinitis: A Nationwide Case–Control Study

ABSTRACT Introduction Inflammatory bowel disease (IBD) has been associated with several allergic diseases, including atopic dermatitis, allergic rhinitis, and asthma. However, the correlations between these conditions vary—some are positively correlated, and some are negatively correlated. To address these discrepancies, this study explored the risk of IBD in patients with allergic diseases. Methods Data were collected from the Taiwan National Health Insurance Research Database, which contains data on approximately 99% of Taiwan's population. Patients with new‐onset IBD and matched controls were enrolled. Data on comorbidities, demographics, and corticosteroid use were collected. Statistical analysis included conditional logistic regression analysis. Results In total, 300 patients with IBD and 2400 patients without IBD were enrolled. Atopic dermatitis (OR: 5.73, 95% CI: 1.69–19.48), allergic rhinitis (OR: 1.72, 95% CI: 1.06–2.79), chronic kidney disease (OR: 3.04, 95% CI: 1.15–8.04), and ischemic heart disease (OR: 1.97, 95% CI: 1.20–3.26) were associated with an increased risk of IBD. Among patients with atopic dermatitis or allergic rhinitis, the risk of IBD was higher for those aged < 65 years, men, or those not using corticosteroids. Conclusion This study highlights an associated risk of IBD in patients with atopic dermatitis and allergic rhinitis.