Inclusion Criteria:

• * ≥13 to 65 years of age (inclusive) for PS, ≥13 for AD and NA, male or female
• * Optional Bx sub study - only adults (18-65 yrs; inclusive only)
• * Able to understand protocol and give consent
• * Able to keep clinic/study appointments and comply with study related procedures
• * Must be able to read, speak, and understand English
• * Chronic AD, according to the American Academy of Dermatology (AAD) Consensus Criteria (Eichenfield 2014), that has been present for at least 1 year before the enrollment visit
• * Chronic PS, according to the AAD Consensus Criteria (Menter et al 2008 (section 1)), that has been present for at least 1 year before the enrollment visit.
• * AD subjects: have active lesions on upper extremities, lower extremities, or trunk and a total disease severity of high moderate-to-severe (EASI ≥12)
• * PS subjects: have active lesions on upper extremities, lower extremities, or trunk and a total disease severity of high moderate-to-severe (PASI ≥7)

Exclusion Criteria:

• * Unwilling and/or unable to complete informed consent process
• * \<13 or \> 65 years of age for PS, \>13 for AD and NA
• * AD subjects: disease without upper extremity, lower extremity, or trunk lesions
• * AD subjects: total disease severity less than moderate (EASI \<12), depending on enrollment
• * PS subjects: disease without upper extremity, lower extremity, or trunk lesions
• * PS subjects: total disease severity less than moderate (PASI \<7), depending on enrollment
• * Control subjects: diagnosed with an inflammatory skin disease
• * Severe concomitant illness(es) that, in the investigator's judgment, would adversely affect the individual's participation in the study (Ex: HIV infection, autoimmune disease, severe heart failure, Hx of malignancy (other than in situ cervical cancer or basosquamous skin cancer), etc.)
• * Recent bacterial, fungal, or viral infection requiring systemic therapies (PO, IV or IM) within the last month.
• * Subjects with a history of serious life-threatening reaction to tape or adhesives may be enrolled but cannot undergo Tape stripping procedure and will therefore only have a baseline TEWL measurement.
• * (For Skin biopsy substudy only) - Subjects with history of keloid formation or allergy to lidocaine.