Background: Atopic dermatitis is a paradigmatic chronic inflammatory skin disease characterized by a complex pathophysiology. The clinical feature of atopic dermatitis varies depending on the age of the patient. Serum IgE level is useful biomarker to appreciate the sensitization profile of patient with allergic diseases. Objectives: We investigated to identify the changes in serum IgE level according to age in patients with atopic dermatitis in Korea. Methods: We included 779 patients who were diagnosed with atopic dermatitis according to the criteria of Hanifin & Rajka and tested serum IgE level registered Department of Dermatology, Nowon Eulji Medical Center between January 2013 and May 2018. We defined serum IgE level under 200 kU/L indicate intrinsic atopic dermatitis and 200kU/L or/and above indicate extrinsic atopic dermatitis. Results: The patients with intrinsic atopic dermatitis were more common until early childhood (2-6 years). From childhood, percentage of extrinsic atopic dermatitis began to increase to 51.3%. In adolescent, patients with extrinsic atopic dermatitis were twice as many as those with intrinsic atopic dermatitis and 1.22 times more in young adult. From adult, the proportion of patient with intrinsic atopic dermatitis increased again. Conclusion: We suggest that there might be some associations between changes of clinical feature of atopic dermatitis and changes of serum IgE level according to age.