AD is characterized by chronic skin inflammation and infections. It is hypothesized that AD is caused by irritants in the environment and that symptoms of EH become worse with stress and changes in hormone levels. This study will examine skin cells collected from study participants to determine the risk factors for EH that are present in people with AD who develop EH.

This study will examine dendritic cells (DC) from the skin and blood of study participants to determine the differences between DCs of study participants. This study will recruit four types of participants:

• Group 1 will include participants with AD and recurrent herpes simplex virus (HSV)
• Group 2 will include participants with recurring HSV infections but without EH
• Group 3 will include participants with AD but without EH or HSV infection
• Group 4 will include participants in good general health without AD, EH, or HSV infection

At the single study visit, skin and blood collection will occur.

Inclusion Criteria for Participants with AD:

• Diagnosis of AD as defined by ADVN standardized diagnostic criteria who fall into one of the following categories:

  1. Recurrent, clinically manifested HSV infection with EH
  2. Recurrent, clinically manifested HSV infection without EH
  3. No recurrent, clinically manifested HSV infection or EH infection

Inclusion Criteria for All Participants

• Residing in Germany
• Good general health other than having an atopic disease
• Caucasian

Exclusion Criteria for All Participants:

• Systemic immunosuppressive drugs or chemotherapy 30 days prior to study entry
• Oral and topical corticosteroids (including inhaled agents), antibiotics, antivirals, anti-inflammatory biologics (e.g., alfacept, etanercept), topical doxepin, topical coal tar preparations, or topical phosphodiesterase inhibitors 14 days prior to study entry
• Immunotherapy
• Antibiotics, antivirals, immune enhancers (e.g., imiquimod), or calcineurin inhibitors within 7 days prior to study entry
• Phototherapy (e.g., ultraviolet light B [UVB], psoralen plus ultraviolet light A [PUVA]) 30 days prior to study entry
• Cancer, autoimmune diseases, or immunodeficiency
• Active fungal, bacterial, or viral infections at screening
• Any skin diseases other than AD that might compromise the stratum corneum barrier (e.g., ichthyosis, bullous disease, psoriasis, skin cancer)
• Mental illness or a history of drug or alcohol abuse that, in the opinion of the investigator, would interfere with the participant’s ability to comply with study requirements
• Weigh less than 40 kg (88.2 lb)
• Anxiolytic agents
• Antidepressants
• Pregnancy or breastfeeding