Background and purpose: The authors noted that chronic actinic dermatitis (CAD) increased in connection with increased sun exposure and believed that there may be a correlation between the two. The purpose of this study was to determine the relationship between increased sun exposure and CAD. We also applied a clinical severity scoring system to determine the correlation with various laboratory parameters. Materials and methods: We investigated trends in sun exposure in Pusan during an 18-year period. We conducted photopatch/patch testing in 51 CAD patients. We also determined the total IgE, percentage of eosinophils, and chemokine receptor profiles in the peripheral blood and analyzed correlations between laboratory data and the clinical severity of CAD. Results: A close correlation was demonstrated between the number of CAD patients and increased sun exposure. Positive patch test reactions and positive photopatch reactions were observed in 35 and 41 of the 51 tested patients, respectively. The total IgE levels were higher in the severe group than in the others. CCR4 expression increased in parallel with clinical severity. Conclusion: Korean patients may have increased susceptibility to CAD with increased sun exposure. We believe that the majority of the CAD patients tested had photoallergy and contact allergy. The clinical severity seemed to correlatewell with the total IgE level and CCR4 expression.