The Impact of Dietary Salt on the Severity of Eczema (iDOSE)

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

Study Overview

• Status: Not yet recruiting
• Conditions: Eczema; Atopic Dermatitis
• Intervention / Treatment: Drug: Sodium chloride tablets; Other: Placebo Tablets

Detailed Description

The central hypothesis of this proposal is that excess dietary sodium (consumed primarily as salt) is concentrated in the skin as a physiologic response to poor barrier function, and that a low-sodium diet can improve eczema severity.

The study will recruit 40 individuals (10 healthy participants, 30 with moderate-severe atopic dermatitis) and follow them to identify factors associated with skin sodium storage.

All participants will be counseled on how to follow a low-sodium diet for 24 weeks. After 12 weeks on the diet alone, they will be asked to add daily tablets in a self-controlled cross-over design. Participants will be randomized in equal groups to either start with sodium tables or placebo tablets. One group will receive sodium tablets for weeks 13-17, no tablets for a washout period during weeks 18-19, then placebo tablets for weeks 20-24. The other group will receive placebo tablets for weeks 13-17, no tablets for a washout period during weeks 18-19, then sodium tablets for weeks 20-24. Sodium consumption will be evaluated using dietary recall questionnaires and urine biomarkers, skin sodium concentration will be measured using a non-invasive sodium MRI technique, and eczema activity and severity will be measured using multiple patient-reported outcomes and clinician scores.

To test the hypothesis that the low-sodium DASH diet improves eczema severity, we will compare eczema severity before and after the 12-week low-sodium dietary intervention. As secondary objectives, we will also test whether increases in dietary sodium administered as sodium chloride tablets during the second 12-week study period are associated with increases in skin sodium concentration corresponding to eczema severity, and whether there are protein biomarkers in the skin or blood that are associated with changes in dietary sodium, skin sodium concentration, and/or eczema severity.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Katrina Abuabara, MD; Phone Number: 415-514-9769; Email: katrina.abuabara@ucsf.edu
• Study Contact Backup: Name: Alicia Hamblin, BS; Phone Number: 925-549-7889; Email: Alicia.Hamblin@ucsf.edu

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94115
      • San Francisco VA Medical Center
      • Contact: Katrina Abuabara, MD; Phone Number: 415-514-9769; Email: katrina.abuabara@ucsf.edu
      • Contact: Alicia Hamblin, BS; Email: Alicia.Hamblin@ucsf.edu
    • San Francisco, California, United States, 94511
      • UCSF Mt Zion Campus
      • Contact: Katrina Abuabara, MD; Phone Number: 415-514-9769; Email: katrina.abuabara@ucsf.edu
      • Contact: Alicia Hamblin, BS; Email: Alicia.Hamblin@ucsf.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

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 <60 mL/min)
• Medications that influence sodium excretion (e.g., diuretics or SGLT2 inhibitors)
• Antibiotic or immunomodulatory medications within the last month
• Contraindications to sodium tablets

(Topical medications used exclusively on the head/neck or hands/feet (e.g., antifungal nail treatment, antidandruff shampoo, acne cleansers) are acceptable. Topical and systemic eczema treatments are acceptable if the participant has been on a stable dose for at least 2 months and still meets the severity entry criteria. Patients on dupilumab will not be excluded if they have been on dupilumab for at least two months and still meet the disease severity inclusion criteria.)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sodium tablets first; Participants will be randomized to receive sodium tablets for weeks 13-17, no tablets for a washout period during weeks 18-19, then placebo tablets for weeks 20-24.	Drug: Sodium chloride tablets; During the 5-week long sodium tablet intervention period, participants will receive five 1 g sodium chloride tablets each morning and four 1 g sodium chloride tablets each evening. Each sodium chloride tablet will contain 0.394 g or 17 mmol of sodium.; Other: Placebo Tablets; During the 5-week long placebo period, participants will receive five placebo tablets each morning and four placebo tablets each evening
Experimental: Placebo tablets first; Participants will be randomized to receive placebo tablets for weeks 13-17, no tablets for a washout period during weeks 18-19, then sodium tablets for weeks 20-24.	Drug: Sodium chloride tablets; During the 5-week long sodium tablet intervention period, participants will receive five 1 g sodium chloride tablets each morning and four 1 g sodium chloride tablets each evening. Each sodium chloride tablet will contain 0.394 g or 17 mmol of sodium.; Other: Placebo Tablets; During the 5-week long placebo period, participants will receive five placebo tablets each morning and four placebo tablets each evening

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Eczema severity	Eczema severity will be measured by the Eczema Area Severity Index (EASI). The score range is 0-72 and higher scores indicate more severe eczema.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Skin sodium concentration	Skin sodium concentration (mmol/L) will be measured via non-contrast sodium MRI; change in the value after the interventions and mean values between groups will be compared	6 months
Protein biomarkers	Fold-changes in protein biomarkers extracted from skin tape strips and blood will be compared; change in the value after the interventions and mean values between groups will be compared	6 months
Atopic dermatitis severity measured by POEM score	Atopic dermatitis severity will be tracked via assessments at clinic visits and via virtual monthly assessments using the Patient Oriented Eczema Measure (POEM). The POEM score ranges from 0-28 and higher scores indicate more severe atopic dematitis; change in the score after the interventions and mean scores between groups will be compared.	6 months
Atopic dermatitis control measured by mean RECAP score	Atopic dermatitis control will be measured at participant visits using the Recap of Atopic Eczema (RECAP) measure of long term control. Scores range from 0-28, and higher scores indicate more severe atopic dermatitis; change in the score after the interventions and mean scores between groups will be compared.	6 months
Participant-reported itch score	Atopic dermatitis-associated itch will be assessed at clinic visits using the numerical rating score for itch (NRS 11). The range for the NRS is 0-10, and higher scores indicate more severe itch / worse disease; change in the score after the interventions and mean scores between groups will be compared.	6 months
Skin-related quality of life score	Skin-related quality of life will be measured at participant visits using the Dermatology Life Quality Index (DLQI). Scores range from 0-30, and higher scores indicate worse outcomes; change in the score after the interventions and mean scores between groups will be compared.	6 months

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Collaborators: United States Department of Defense
• Investigators: Principal Investigator: Katrina Abuabara, MD, University of California, San Francisco

Study record dates

Study Major Dates

• Study Start (Estimated): March 6, 2026
• Primary Completion (Estimated): March 5, 2028
• Study Completion (Estimated): May 5, 2028

Study Registration Dates

• First Submitted: February 25, 2026
• First Submitted That Met QC Criteria: February 25, 2026
• First Posted (Actual): March 3, 2026

Study Record Updates

• Last Update Posted (Actual): March 17, 2026
• Last Update Submitted That Met QC Criteria: March 13, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: diet; sodium; salt
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Immune System Diseases; Hypersensitivity, Immediate; Hypersensitivity; Skin Diseases; Skin Diseases, Genetic; Skin Diseases, Eczematous; Dermatitis; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Skin and Connective Tissue Diseases; Dermatitis, Atopic; Eczema; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Chlorides; Hydrochloric Acid; Sodium Chloride
• Other Study ID Numbers: 25-43778; HT9425-25-1-0465 (Other Grant/Funding Number: Department of Defense)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All IPD that underlie the results in a publication
• IPD Sharing Time Frame: Beginning 1 year and ending 5 years after publication of the results
• IPD Sharing Access Criteria: Researchers interested in accessing data from the project must submit a written resource request via email to the Principal Investigator and sign a Data Use Agreement. De-identified data will be shared through a secure server.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No