• The identification of variants/haplotypes in candidate genes associated with EH and the characterization of frequencies of variants in priority candidate genes for EH according to African American and Caucasian race. [ Time Frame: 4 years ]
  

• The identification and prioritization of novel genes induced in response to viral infection (HSV/Vaccinia and MCV) in AD subjects and relevant control groups. [ Time Frame: 4 years ]
  

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). The focus of this study is individuals with AD who have a history of EH (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, but instead due to differences in each individual's response to viruses. The purpose of this study is to determine what genetic pathways are responsible for the development of viral skin infections in people with AD using exposure to three viruses: HSV-1, vaccinia, and molluscum contagiosum to stimulate gene expression.

Participants in this study will also be enrolled in the ADVN Biomarker Registry Study. There will be only one clinical visit for this study at which blood and skin samples will be collected. The samples will then be exposed to the viruses and high-throughput genotyping and gene expression profiling experiments will be used to define genetic markers in individuals susceptible to viral infections.

African-American, Caucasion, and Non-Hispanic people ages 1 to 80

Inclusion Criteria:

• Enrollment in ADVN Biomarker Registry Study
• Non-Hispanic and only African American or only Caucasian race
• Parent or guardian willing to provide informed consent, if necessary

Exclusion Criteria:

• History of any systemic illness other than AD.
• Participation of a first degree relative (defined as siblings, half siblings, and parents) already enrolled in the genotyping study unless the subject in question fulfills the diagnostic criteria for ADEH . If a second family member is enrolled because they are ADEH , then the first family member that was enrolled will be removed from the study (if they are not ADEH ).