Pseudoallergen-Free and Low-Histamine Diet in Adolescents With Chronic Spontaneous Urticaria (PAF-LH-CSU)

June 2, 2026 updated by: Ayşe Süleyman, Istanbul University

Clinical Response to a Histamine- and Pseudoallergen-Restricted Diet in Patients With Chronic Urticaria

The goal of this clinical trial is to learn whether a histamine- and pseudoallergen-restricted diet can help reduce symptoms in people with chronic urticaria. It will also learn whether this diet changes the need for urticaria medication.

The main questions it aims to answer are:

Does the diet lower urticaria activity, including hives and itching?

Does the diet improve disease control and quality of life?

Does the diet change the need for urticaria medication?

Which clinical or laboratory factors may affect response to the diet?

There is no comparison group. Researchers will compare participants' symptoms before and after the diet.

Participants will:

Follow a structured histamine- and pseudoallergen-restricted diet

Continue their usual urticaria treatment as recommended by their doctor

Record or report their urticaria symptoms during follow-up

Visit the clinic for assessment of symptoms, disease control, quality of life, medication use, and laboratory findings.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

Chronic spontaneous urticaria in children is a heterogeneous condition characterized by recurrent wheals, angioedema, or both for more than six weeks without a consistent external trigger. Although second-generation H1-antihistamines are the mainstay of treatment, disease activity may persist in some children despite standard care.

Dietary factors, including histamine-rich foods, histamine-releasing foods, and pseudoallergens such as selected additives, preservatives, colorants, and naturally occurring food components, have been proposed as potential aggravating factors in a subset of patients. However, the clinical value of dietary restriction in pediatric chronic spontaneous urticaria remains uncertain, and better evidence is needed to determine whether a time-limited dietary approach provides additional benefit.

This randomized controlled study will evaluate a structured low-histamine and pseudoallergen-free diet as an adjunct to standard guideline-based care in children with chronic spontaneous urticaria. The comparator group will receive standard care with general age-appropriate healthy eating advice, without specific restriction of histamine-rich or pseudoallergen-containing foods during the primary comparison period.

All participants will continue to receive standard clinical care according to current urticaria management principles. Antihistamine treatment will be permitted according to clinical need. The study will also explore whether baseline clinical and laboratory characteristics, including autologous serum skin test status and routine inflammatory markers, are associated with response to the dietary intervention.

Because this is a pediatric dietary study, the dietary intervention will be standardized, time-limited, and implemented with parental guidance. Unnecessary prolonged dietary restriction will be avoided.

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Fatih
      • Istanbul, Fatih, Turkey (Türkiye), 34100
        • Istanbul University, Istanbul Faculty of Medicine, Department of Pediatric Allergy and Immunology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

IInclusion Criteria:

Children aged 1 to 18 years Diagnosis of chronic spontaneous urticaria Disease duration of at least 6 weeks Presence of active urticaria symptoms at enrollment Ability of the child and/or parent/caregiver to complete symptom and diet follow-up forms Ability and willingness of the family to follow the assigned dietary recommendation Written informed consent from parent or legal guardian Assent from the child when applicable

Exclusion Criteria:

Pure chronic inducible urticaria Urticaria secondary to an identified trigger IgE-mediated food allergy requiring a specific elimination diet Active infection or parasitic disease Oral corticosteroid use within the previous 4 weeks Current or recent biological treatment for chronic urticaria Coeliac disease Inflammatory bowel disease Known systemic mast cell disease Severe chronic systemic disease affecting diet, growth, or follow-up Significant malnutrition or a medical condition requiring a special diet Pregnancy or lactation in postmenarchal adolescents Inability or unwillingness of the child or family to adhere to the assigned dietary recommendation Incomplete follow-up data

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Low-histamine and pseudoallergen-free diet group
Children with chronic spontaneous urticaria assigned to this arm will receive a structured low-histamine and pseudoallergen-free diet in addition to standard guideline-based clinical care.
Behavioral: Intervention Name: Low-histamine and pseudoallergen-free diet
Participants assigned to the intervention group will receive a structured low-histamine and pseudoallergen-free diet for 4 weeks in addition to standard guideline-based clinical care. The diet will restrict histamine-rich foods, foods considered to promote histamine release, and foods containing common pseudoallergen sources such as selected additives, preservatives, colorants, and naturally occurring pseudoallergen-rich foods. Antihistamine treatment will be permitted according to clinical need.
Active Comparator: General dietary advice control group
Children with chronic spontaneous urticaria assigned to this arm will receive standard guideline-based clinical care with general age-appropriate healthy eating advice, without specific restriction of histamine-rich or pseudoallergen-containing foods during the primary comparison period.
Behavioral: General healthy eating advice
Participants assigned to the control group will receive standard guideline-based clinical care together with general age-appropriate healthy eating advice. No specific restriction of histamine-rich foods, histamine-releasing foods, or pseudoallergen-containing foods will be recommended during the primary 4-week comparison period. Antihistamine treatment will be permitted according to clinical need.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in weekly urticaria activity score
Time Frame: Baseline to week 4
Change in weekly urticaria activity score (UAS7) from baseline to week 4 will be compared between the low-histamine and pseudoallergen-free diet group and the general healthy eating advice control group.
Baseline to week 4
Change in urticaria control test score
Time Frame: Baseline to week 4
Change in urticaria control test (UCT) score from baseline to week 4 will be compared between the low-histamine and pseudoallergen-free diet group and the general healthy eating advice control group.
Baseline to week 4

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in dermatology quality-of-life score
Time Frame: Baseline to week 4
Change in age-appropriate dermatology quality-of-life score from baseline to week 4 will be compared between the low-histamine and pseudoallergen-free diet group and the general healthy eating advice control group.
Baseline to week 4
Change in antihistamine requirement
Time Frame: Baseline to week 4
Change in antihistamine requirement from baseline to week 4 will be compared between the two study groups. Antihistamine use will be assessed according to the need for standard-dose or increased-dose second-generation H1-antihistamine treatment.
Baseline to week 4
Proportion of participants achieving clinical response
Time Frame: Baseline to week 4
The proportion of participants achieving clinical response at week 4 will be compared between the two study groups. Clinical response will be defined as at least a 50% reduction in weekly urticaria activity score from baseline to week 4.
Baseline to week 4
Dietary adherence
Time Frame: Basaline to week 4.
Adherence to the assigned dietary recommendation will be assessed during the 4-week intervention period using a dietary adherence checklist or dietary diary.
Basaline to week 4.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Istanbul University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 24, 2025

Primary Completion (Estimated)

November 24, 2026

Study Completion (Estimated)

January 1, 2027

Study Registration Dates

First Submitted

June 2, 2026

First Submitted That Met QC Criteria

June 2, 2026

First Posted (Actual)

June 8, 2026

Study Record Updates

Last Update Posted (Actual)

June 8, 2026

Last Update Submitted That Met QC Criteria

June 2, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • ASST-PAF-LH-CSU-2025-3729877
  • 2025-3729877 (Other Identifier: Istanbul University, Istanbul Faculty of Medicine Clinical Research Ethics Committee)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be publicly shared because of privacy and ethical restrictions related to pediatric clinical data. De-identified data may be considered upon reasonable request and subject to approval by the study investigators and relevant institutional authorities.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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