Role of Antimicrobial Peptides in Host Defense Against Vaccinia Virus

Inclusion Criteria for Participants With AD: * 2 years of age or older * History of active or inactive AD OR eczema herpeticum, as defined by the ADVN standardized diagnostic criteria * Parent or guardian willing to provide informed consent, if applicable * Male or female of any race and ethnicity Inclusion Criteria for Participants With Asthma or Psoriasis, and for non-atopic controls: * 18 years or older * History of psoriasis OR history of asthma not requiring systemic medications * Parent or guardian willing to provide informed consent, if applicable * Male or female of any race and ethnicity Exclusion Criteria: * Oral corticosteroids or any systemic immunosuppressive or immunomodulatory medication within 28 days prior to study entry * Immunotherapy within 3 months prior to study entry * History of bleeding disorder * Aspirin, oral antihistamines, oral antibiotics, oral cyclosporine, or topical medications within 7 days of screening visit including, but not restricted to, Protopic, Elidel, topical corticosteroids, and topical antibiotics * Anxiolytic agents and antidepressants within 2 days of screening visit * Diabetic requiring medication * Autoimmune or immunodeficiency * Active fungal, bacterial, or viral infections within 7 days prior to study entry * Active systemic cancer. Participants with uncomplicated nonmelanoma skin cancer are not excluded. * Theophylline or leukotriene antagonists within 24 hours of screening visit * Received any vaccination within 30 days prior to study entry * Known lidocaine allergy * Previously vaccinated for smallpox * Pregnant or breastfeeding