Inclusion Criteria:  ≥ 18 years of age at enrollment Able to read and communicate in English Willing and able to provide informed consent Willing to participate in the collection of patient-reported outcomes for up to 2 years For patient Cohort 1: diagnosed with clinically-confirmed AD that is mild-to-moderate (i.e., consistent with a investigator global assessment of 2 or 3) in the judgement of the treating physician For patient Cohort 2: diagnosed with clinically-confirmed moderate-to-severe AD and newly initiating an advanced systemic therapy for AD  Exclusion Criteria:  Current (or planned) participation in an interventional clinical trial where treatment and/or management of AD is being dictated by a protocol Patient is not expected to be actively followed (i.e., seen every 6 to 12 months as part of routine care) at the site for AD