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Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease that has been shown to be associated with allergic comorbidities. However, studies examining comorbidities in patients with AD are incomplete, which may contribute to suboptimal care.

Objectives: The objective was to compare the risk of developing different allergic and nonallergic comorbidities among adult patients with AD to that of a matched reference cohort in Sweden.

Methods: This was a nationwide population-based cohort study using longitudinal data from primary and specialist care registers. AD patients were identified by confirmed diagnosis in primary or specialist care. A non-AD reference cohort was randomly drawn from the general population and matched 1:1 with the AD patients on age, gender, and geographical region. The risk of developing the following conditions was evaluated: asthma, food hypersensitivity, allergic rhinitis, neurological disorders, psychiatric disorders, infections, immunological & inflammatory disorders, type 1 diabetes (T1D), type 2 diabetes (T2D), endocrine & metabolic disorders, skeletal disorders, ocular disorders, cardiovascular diseases, and malignancies.

Results: This study included 107,774 AD patients [mild-to-moderate (n = 92,413) and severe (n = 15,361)] and an equally-sized reference cohort. AD patients displayed a higher risk of developing comorbid conditions for all investigated categories, except for T1D, compared with the reference cohort. The highest risk compared with the reference cohort was observed for allergic comorbidities followed by immunological & inflammatory disorders (hazard ratio: 2.15) and infections (hazard ratio: 2.01). Patients with AD also had higher risk of developing multiple comorbidities (2 or more). The risk of comorbidity onset increased alongside AD severity and patients with active AD were associated with increased risk of comorbidity onset compared with patients in remission.

Conclusions: AD patients are at an increased risk of developing many comorbidities that extend beyond allergic conditions. This study highlights the need for interdisciplinary follow-up of comorbidities in the management of AD patients to reduce overall patient burden.