Background: Atopic dermatitis (AD) is a common inflammatory skin condition. While previous publications have examined healthcare expenses, large data regarding patient demographics, healthcare use and drug prescriptions are limited. Objective: To examine demographics, healthcare use and drug prescriptions in children and adults with hospital-diagnosed AD. Methods: Danish nationwide registries were cross-linked to access demographic, healthcare and drug prescription data on children and adults with hospital-diagnosed AD (ICD-10 code L20). The diagnostic code for AD used in this study was validated by reviewing medical charts. Results: We identified 9704 children (time period 1997–2012) and 5558 adults (time period 1997–2007) with hospital-diagnosed AD. The diagnostic code L20 had a positive predictive value of 95%. Among children with AD, a larger proportion came from less resourceful families and had immigrant parents from non-European countries. In adults, we observed an opposite tendency. Topical and systemic antibiotics were used relatively frequent in both children and adults with AD. The use of prednisolone and other systemic anti-inflammatory therapy was substantially higher in adults with AD than in children. Limitations: We were unable to identify and describe patients treated by general and private practitioners. Conclusion: There exist significant differences in social predictors for AD and the use of AD medication between children and adults with hospital-diagnosed AD in Denmark. The diagnostic code for AD appears to be valid in Danish registries.