The guidelines for the treatment of atopic dermatitis (AD) issued by the Japanese Dermatological Association (JDA), which are basically designed for dermatologists, were first prepared in 2000 and revised in 2016. The guidelines for AD of the Japanese Society of Allergology USA), which are basically designed for allergologists, including internists, otorhinolaryngologists, ophthalmologists, and dermatologists, were first prepared in 2009 and revised in 2014. In this article, I review the definition, pathophysiology, etiology, epidemiology, diagnosis, severity classification, examination for diagnosis and severity assessment, and treatments for AD in Japan according to these two guidelines for AD (JDA and JSA). Based on the definition and diagnostic criteria for AD of the JDA, patients meeting three basic criteria, 1) pruritus, 2) typical morphology and distribution of the eczema, and 3) chronic or chronically relapsing course, are regarded as having AD. Treatment measures for AD basically consist of drug therapy, skin care, and elimination of exacerbating factors. Drugs that potently reduce AD-related inflammation in the skin are topical corticosteroids and tacrolimus. It is most important to promptly and accurately reduce inflammation related to AD by using these topical anti-inflammatory drugs. Proactive therapy refers to a treatment method in which, after inducing remission, a topical corticosteroid or tacrolimus ointment is intermittently applied to the skin in addition to skin care with moisturizers in order to maintain remission.