Background: Alopecia areata (AA) and atopic dermatitis (AD) are chronic skin diseases where the suboptimal medication adherence (MA) may result in poor clinical outcomes. Objective: To assess the impact of AA on MA among adults compared to AD. Methods: Patient reported MA of adults with AA were compared with AD. Patients were identified from the Danish Skin Cohort, a nationwide prospective cohort of dermatological patients in Denmark. We used the Medication Adherence Report Scale- 5, a self-reporting questionnaire, to assess MA. Demographic and disease characteristics were collected. Logistic regression was conducted. Results: Patients with AA reported higher MA than AD (mean 21.81 vs 18.29). Logistic regression analyses showed AA diagnosis had a statistically significant positive effect on MA (odds ratio = 3.94, 95% CI 2.01-8.89). Men reported significantly higher MA (odds ratio = 1.49, 95% CI 1.14-1.94). Current disease severity did not impact MA. Limitations: Data were self-reported by patients. Data regarding the specific treatment undergone by patients were not available. Conclusion: Patients with AA have significantly higher MA compared to patients with AD. The stability of AA patients’ symptoms may lead to higher MA due to a desire for disease control. Conversely, the sporadicity of AD symptoms could negatively affect adherence, causing fluctuations in medication use.