The purpose of this study is to look at how defects in the skin barrier and immune response affect risk for skin infections.

Participants will be classified into 4 groups based on Atopic Dermatitis (AD)/Non-Atopic (NA) status and Staphylococcus aureus (S. aureus) colonization (negative or positive):

• AD S. aureus negative
• AD S. aureus positive
• NA S. aureus negative and
• NA S. aureus positive.

Atopic dermatitis, also called eczema, is a disease in which the skin is dry and scaly with severe itching. People with atopic dermatitis have defects in the skin barrier as well as defects in the immune system which fights off skin infections. People who have atopic dermatitis often have complications from viral and bacterial skin infections, such as recurring Staphylococcus aureus (S. aureus), or Staph infections.

The study will compare the skin barrier and immune response of people with and without atopic dermatitis in relation to whether Staph bacteria is growing on their skin.

Inclusion Criteria:

Participants fulfilling all of the following criteria are eligible for enrollment-

• Non-Hispanic Caucasian males and females 18 to 60 years of age, inclusive, at the time of Enrollment
• Who are enrolled in the ADRN Registry study
• Who have active AD (lesions present) with or without a history of Eczema Herpeticum (EH) as defined in the ADRN Standard Diagnostic Criteria OR who meet criteria for the NA diagnostic group as defined in the ADRN Standard Diagnostic Criteria
• Who are willing to sign the informed consent form prior to initiation of any study procedures.

Exclusion Criteria:

Participants fulfilling any of the following criteria are not eligible for enrollment-

• Who are pregnant
• Who have an active systemic malignancy. Uncomplicated non-melanoma skin cancer and melanoma in situ with documentation of complete excision are not exclusionary
• Who have any skin disease other than AD that might compromise the SC barrier (e.g., bullous disease, psoriasis, cutaneous T cell lymphoma [also called Mycosis Fungoides or Sezary syndrome], dermatitis herpetiformis, Hailey-Hailey, or Darier's disease)
• Who have a history of systemic immunological illness (e.g., human immunodeficiency virus [HIV] or systemic lupus erythematosus [SLE]) other than the condition being studied
• Who have active EH or eczema vaccinatum (EV)
• Who have a history of serious or life-threatening reaction to latex, tape, or adhesives
• Who are determined to be not eligible based on the opinion of the Investigator.

Participants enrolled in the ADRN Registry study (NCT01494142) who fulfill eligibility criteria for this (ADRN04) study