AbstractBackgroundAtopic dermatitis (AD) and asthma often co‐occur in the same patient, and healthcare utilization is related to disease severity of these diseases.ObjectiveThe objective of the study was to investigate differences in healthcare utilization in adults with concomitant AD and asthma compared to patients with asthma or AD only.MethodsAll Danish adults with a hospital diagnosis of AD, asthma or concomitant AD, and asthma recorded in national registries were included. Healthcare utilization data were obtained in 3‐month intervals from 2 years prior to index date (the date of the first hospital diagnosis) and to 5 years after.ResultsA total of 12 409 patients with AD were included (11 590 with AD only and 819 with concomitant AD and asthma), and 65 539 with asthma only.Adults with concomitant AD and asthma had higher risk of hospitalization for AD (OR 1.38, 95% CI (1.15–1.67), P = 0.001) and asthma (OR 1.16, 95% CI (1.00–1.35), P = 0.047) compared to patients with only AD and asthma, respectively. These patients also had fewer visits in outpatient clinics for AD (OR 0.10, 95% CI (0.08–0.12), P < 0.001) and asthma (OR 0.34, 95% CI (0.29–0.39), P < 0.001) compared to patients with only AD or asthma. Outpatient clinic visits for rhinitis were more frequent among patients with concomitant AD and asthma compared to patients with only AD or asthma.ConclusionAdults with concomitant AD and asthma had different patterns of healthcare utilization compared to adults with AD or asthma alone, suggesting that improvements in management and monitoring may reduce unscheduled healthcare visits and lower healthcare costs.