Increased risk of fibromyalgia in patients with atopic dermatitis: A nationwide longitudinal study

Background Emerging evidence suggests a possible relationship between atopic dermatitis (AD) and fibromyalgia, driven by overlapping mechanisms like chronic inflammation, immune dysregulation, and neuroimmune interactions. While AD is recognised as a common chronic inflammatory condition, its association with fibromyalgia remains under investigation. Aim To investigate the association between AD and subsequent fibromyalgia risk, and to examine how this relationship varies across different age groups and AD severity levels. Methods Using the Taiwan National Health Insurance Research Database, we conducted a nationwide cohort study, including 4,147 patients with AD aged ≥10 years without psychiatric history and 41,470 age- and sex-matched controls from 1995 to 2010. Stratified Cox-regression analysis with adjustment for potential confounders was performed to assess fibromyalgia risk through 2013. Results Patients with AD showed a significantly increased risk of developing fibromyalgia (adjusted hazard ratio [HR]: 7.12, 95% confidence interval [CI]: 5.37-9.43) based on Cox regression analysis. The risk was highest in patients under 20 years old (HR: 13.59, 95% CI: 6.85-26.97), followed by those aged 20-59 years (HR: 6.31, 95% CI: 4.4-9.03), and lowest in patients over 60 years (HR: 3.89, 95% CI: 1.64-9.19). The severity of AD also influenced risk, with higher severity associated with a greater likelihood of fibromyalgia (mild AD HR: 6.97, 95% CI: 5.1-9.53; moderate-to-severe AD HR: 7.72, 95% CI: 4.18-14.27). Limitation The study was limited by potential underestimation of fibromyalgia cases, lack of detailed clinical information due to ICD-9-CM code-based identification, and absence of data on important confounding factors. Conclusion This study demonstrates a significant association between AD and increased fibromyalgia risk, with younger age and greater disease severity correlating with higher risk. These findings suggest shared neuroinflammatory pathways and immunological mechanisms, warranting further investigation.