People with atopic dermatitis (AD), or eczema, are susceptible to skin infections and inflammations. Some individuals with AD develop a condition known as eczema herpeticum (EH) following exposure to the herpes simplex virus (HSV). The purpose of this study is to identify the genetic determinants that lead people with AD to develop EH and similar conditions caused by other viruses.

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. To explore this objective, exposure to three viruses will be used to stimulate gene expression: HSV-1, vaccinia, and molluscum contagiosum.

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/or skin samples may 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.

• People with AD will provide samples that will be exposed to HSV-1 to stimulate gene expression
• People with AD will provide samples that will be exposed vaccinia to stimulate gene expression
• People with AD will provide samples that will be exposed molluscum contagiosum to stimulate gene expression

• Baker BS. The role of microorganisms in atopic dermatitis. Clin Exp Immunol. 2006 Apr;144(1):1-9. Review.
• Kim BE, Leung DY, Streib JE, Boguniewicz M, Hamid QA, Howell MD. Macrophage inflammatory protein 3alpha deficiency in atopic dermatitis skin and role in innate immune response to vaccinia virus. J Allergy Clin Immunol. 2007 Feb;119(2):457-63. Epub 2006 Dec 4.
• Porter CD, Muhlemann MF, Cream JJ, Archard LC. Molluscum contagiosum: characterization of viral DNA and clinical features. Epidemiol Infect. 1987 Oct;99(2):563-7.
• Umene K, Yoshida M, Sakaoka H. Comparison of the association with eczema herpeticum in the two predominant genotypes of herpes simplex virus type 1. J Med Virol. 1996 Aug;49(4):329-32.

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, excluding AD
• Participation of a first degree relative already enrolled in the genotyping study unless the subject in question fulfills the diagnostic criteria for ADEH+. More information on this criterion can be found in the protocol.