AD is a chronic inflammatory skin disorder characterized by recurrent viral skin infections. However, people with AD do not all develop the same infections. For example, some people with AD who receive the smallpox vaccine develop a life-threatening condition known as eczema vaccinatum (EV). This study focuses on individuals with AD who also have a history of eczema herpeticum (ADEH+), a condition similar to EV. It is unlikely that the differences in the development of skin infections are due to differences in viral exposure, and instead due to differences in each individual's response to viruses. The purpose of this study is to determine the genetic pathways which are responsible for the development of viral skin infections in people with AD.