People of good general health, living in Germany

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