The Impact of Salt Intake on Sodium in the Skin and Inflammatory Skin Disease (SIS-ISD)

The goal of this clinical trial is to demonstrate the feasibility of a trial that examines the impact of changes in dietary sodium intake on skin sodium levels, atopic dermatitis, and psoriasis. In addition, it aims to generate preliminary data to begin to answer the following questions:

1. Is there an association between skin sodium concentration and atopic dermatitis and psoriasis severity?
2. Are changes in dietary sodium are associated with changes in skin sodium concentration and atopic dermatitis and psoriasis severity?

Researchers will 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 13-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
• Visit the clinic up to 4 times to answer questionnaires, provide bio samples, complete dietary recalls, and undergo non-contrast sodium MRI

Study Overview

• Status: Not yet recruiting
• Conditions: Psoriasis; Atopic Dermatitis (Eczema)
• 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 inflammatory skin disease severity. This study is meant to generate pilot data to complement the iDOSE trial (NCT07447063). The study will recruit 50 individuals (10 participants with atopic dermatitis, 10 with psoriasis, and up to 30 'healthy' individuals without skin disease) and measure skin sodium concentration using a non-invasive sodium MRI technique. Healthy individuals will only undergo sodium scans at Visit 1. Participants with atopic dermatitis and psoriasis will be counseled on how to follow the DASH low-sodium diet and asked to maintain the diet for the duration of the 13-week study. After a 1-week wash-in period on the diet alone, they will be asked to add daily sodium chloride 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 2-6, no tablets for a washout period during weeks 7-8, then placebo tablets for weeks 9-13. The other group will receive placebo tablets for weeks 2-6, no tablets for a washout period during weeks 6-8 then sodium tablets for weeks 8-13. Sodium consumption will be evaluated using dietary recall questionnaires and urine biomarkers and eczema and psoriasis activity and severity will be measured using validated severity scores and patient-reported outcomes.

• Study Type: Interventional
• Enrollment (Estimated): 50
• 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; Phone Number: 925-549-7889; Email: Alicia.Hamblin@ucsf.edu

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94121
      • San Francisco VA Medical Center
      • Contact: Katrina Abuabara, MD; Phone Number: 415-514-9769; Email: katrina.abuabara@ucsf.edu
      • Contact: Alicia Hamblin; Phone Number: 925-549-7889; Email: Alicia.Hamblin@ucsf.edu
      • Principal Investigator: Katrina Abuabara, MD
    • San Francisco, California, United States, 94115
      • UCSF Mt Zion Campus
      • Contact: Alicia Hamblin; Phone Number: 925-549-7889; Email: Alicia.Hamblin@ucsf.edu
      • Contact: Katrina Abuabara, MD; Email: katrina.abuabara@ucsf.edu
      • Principal Investigator: Katrina Abuabara, MD

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 2-6, no tablets for a washout period during weeks 7-8, then placebo tablets for weeks 9-13.	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 2-6, no tablets for a washout period during weeks 7-8, then sodium tablets for weeks 9-13.	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
Fidelity of low-salt diet	Fidelity of the low-salt diet and sodium tab intervention adherence will be assessed based on sodium levels from food recall questionnaires and 24-hour urine sodium samples.	4 months
Feasibility measured by recruitment rates and exclusion and non-participation reasons	To assess feasibility, we will calculate recruitment rates and reasons for exclusion and non-participation will be summarized using descriptive statistics.	4 months
Retention rates	Retention rates will be calculated as the proportion of visits completed. We will compare retention rates by study arm and participant characteristics.	4 months

Secondary 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. Change in the score after the intervention periods will be compared.	4 months
Atopic dermatitis severity measured by POEM score	Atopic dermatitis severity will be tracked via assessments at clinic visits using the Patient Oriented Eczema Measure (POEM). The POEM score ranges from 0-28 and higher scores indicate more severe atopic dermatitis; change in the score after the intervention peroids will be compared.	4 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 intervention periods will be compared.	4 months
Psoriasis severity	Psoriasis severity will be measured by the Psoriasis Area and Severity Index (PASI). The score range is 0-72 and higher scores indicate more severe psoriasis. Change in the score after the intervention periods will be compared.	4 months
Participant-reported psoriasis severity measured by PSI score	Psoriasis severity will be tracked via assessments at clinic visits using the Psoriasis Symptom Inventory (PSI). The PSI score ranges from 0-32 and higher scores indicate more severe psoriasis. Change in the score after the interventions will be compared.	4 months
Presence of psoriatic arthritis	Potential underlying psoriatic arthritis will be assessed using the Psoriasis Epidemiology Screening Tool (PEST). The PEST score ranges from 0-5 and a score of 3 or higher indicates potential psoriatic arthritis; presence of psoriatic arthritis after the interventions and between groups will be compared.	4 months
Participant-reported itch score	Atopic dermatitis or psoriasis-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 will be compared.	4 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 will be compared.	4 months
Clinician-reported overall severity of eczema and psoriasis	Clinician-reported overall severity of eczema and psoriasis will be assessed using the Investigator's Global Assessment (IGA). Scores range from 0-4, and higher scores indicate worse outcomes. Change in the score after the intervention periods will be compared.	4 months

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Collaborators: LEO Foundation
• Investigators: Principal Investigator: Katrina Abuabara, MD, University of California, San Francisco

Study record dates

Study Major Dates

• Study Start (Estimated): March 16, 2026
• Primary Completion (Estimated): March 17, 2028
• Study Completion (Estimated): March 17, 2028

Study Registration Dates

• First Submitted: March 17, 2026
• First Submitted That Met QC Criteria: March 17, 2026
• First Posted (Actual): March 23, 2026

Study Record Updates

• Last Update Posted (Actual): March 23, 2026
• Last Update Submitted That Met QC Criteria: March 17, 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, Papulosquamous; Skin Diseases; Skin Diseases, Genetic; Skin Diseases, Eczematous; Dermatitis; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Skin and Connective Tissue Diseases; Psoriasis; Dermatitis, Atopic; Eczema; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Chlorides; Hydrochloric Acid; Sodium Chloride
• Other Study ID Numbers: 22-36690

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