The Impact of Dietary Salt on the Severity of Eczema

The goal of this clinical trial is to evaluate the feasibility of low-sodium diet to improve eczema severity. The main questions it aims to answer are: * Does a low-sodium diet improve eczema severity? * How does a low-sodium diet impact skin sodium concentration? * Is skin sodium concentration associated with eczema severity? Researchers will ask all participant to follow a low-sodium diet, then compare sodium tablets to a placebo (a look-alike substance that contains no drug) to specifically examine the impact of altering sodium intake. Participants will: * Follow a low-salt diet for the duration of the 24-week study * Take sodium chloride tablets every day for 5 weeks followed by a placebo every day for 5 weeks after a 2-week washout period, or vice versa * Complete up to 4 virtual check-in visits * Visit the clinic 4 times to answer questionnaires, provide bio samples, complete dietary recalls, and undergo non-contrast sodium MRI

Inclusion Criteria: * Participants ages 18 years * Willing and able to undergo non-contrast MRI. Exclusion Criteria: * Contraindications to MRI (such as cardiac pacemakers, claustrophobia, non-compatible intracranial vascular clips, IUDs, or other implants) * A cardiac event in the past 6 months * Impaired function of the liver or kidney (glomerular filtration rate \