RecruitingSodium in the Skin and Atopic DermatitisThe goal of this observational study is to understand factors associated with skin sodium storage in healthy adults and people with atopic dermatitis ages 50 and above. The study is designed to test whether diet and skin barrier function are associated with skin sodium concentration and whether skin sodium concentration is linked to atopic dermatitis and immune profiles over time. Participants will be asked to complete questionnaires, provide bio samples, and undergo non-contrast sodium MRI at 2-3 time points over 3-24 months.