異位性皮膚炎是常見的過敏性疾病，由於反復性的皮膚紅疹及劇烈的癢感，造成失眠及影響工作學習，且經常合併其他的過敏性疾病，如氣喘、過敏性鼻炎等，對個人生活品質、家庭、及社會的不良影響相當大。病因是多因子共同參與，包括基因異常，表皮屏障缺損，環境因子影響等，協同導致異位性皮膚炎的發生。本文除一般論介紹異位性皮膚炎外，並著重於環境因子如何與基因異常及表皮屏障缺損互動，來調控異位性皮膚炎的進展及其病生理機轉。再來，如何透過調節環境因子，如空氣污染、抽菸、食物過敏等，來治療或預防異位性皮膚炎的復發。最後介紹異位性皮膚炎的治療及保濕劑的使用。

Atopic dermatitis is a common allergic disease with recurrent skin rash and intense pruritis, that cause poor sleep and impair working and learning. It is usually associated with other allergic diseases, such as asthma and allergic rhinitis, causing tremendous disease burden to the person, family, and the society. Multiple factors contribute to the pathophysiology of atopic dermatitis, including gene abnormalities, skin barrier impairment, and environmental factor modulation. This article introduces the clinical significance, epidemiology, and disease burden of atopic dermatitis. In addition, this article focuses on how these environmental factors interact with abnormal genetic activations and impaired skin barriers to cause and modulate the progression and course of atopic dermatitis. Through intervention against these environmental factors, including air pollution, smoking, and food allergy, etc., this article opts to prevent the occurrence and recurrence of atopic dermatitis. Finally, we discuss the general treatment of atopic dermatitis and the importance of moisturizers to restore the impaired skin barrier.