Background Atopic dermatitis has been linked to increased risk of many comorbidities. However, the risks of certain comorbidities are still debated. Objective To better characterize the basic demographics, treatment patterns, and associations between atopic dermatitis and comorbidities and to further investigate the influence of severity on comorbidities. Methods We used a sample cohort of 999,992 people from the National Health Insurance Research Database of Taiwan to evaluate atopic dermatitis in the general population. Results A total of 12,780 patients with atopic dermatitis in 2010 were identified. The prevalence was 1.28%. The proportions of severe and moderate cases were 7.43% and 19.26%, respectively. The most commonly used systemic treatment was corticosteroids. Compared with the general population, atopic dermatitis patients showed increased risks of all 9 groups of comorbidities, including autoimmune disorders, atopic disorders, chronic urticaria, ocular disorders, metabolic disorders, hypertensive disorders, ischemic heart disorders, cerebrovascular disorders, and psychiatric disorders. The severity and persistence of atopic dermatitis were correlated with the development of certain comorbidities. Limitations Miscoding and misclassification might have occurred, and only patients with active disease were enrolled. Conclusion Patients with atopic dermatitis have higher risks of various comorbidities. Comprehensive monitoring and treatment plans are needed to better manage these patients.