FASC: Fish Allergy in Spanish Children - A Study of New Cases of Fish Allergy in Children and Adolescents (FASC)

July 22, 2026 updated by: Carmelo Escudero

IgE-Mediated Fish Allergy in Spanish Children and Adolescents: A Multicenter Prospective Study of New-Onset Cases and Sensitization Profiles.

Fish allergy is one of the leading causes of food-induced allergic reactions in children, but the clinical presentation and patterns of sensitization vary considerably among patients and geographical regions. This prospective multicenter observational study aims to characterize children and adolescents with newly diagnosed IgE-mediated fish allergy in Spain.

Clinical information, diagnostic test results, and molecular sensitization profiles will be collected using standardized procedures across participating centers. Molecular allergy assessment will include component-resolved diagnostics to evaluate sensitization to major fish allergens and other relevant allergenic protein families. The study will also assess disease severity, quality of life, and regional differences in sensitization patterns.

The results are expected to improve the understanding of pediatric fish allergy in Spain and contribute to more accurate diagnosis, risk assessment, and personalized management of affected patients.

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Fish allergy is a major cause of IgE-mediated food allergy in children and is associated with a wide spectrum of clinical manifestations, ranging from mild reactions to severe anaphylaxis. Current knowledge of pediatric fish allergy is limited by geographical differences in dietary habits, fish species consumed, and patterns of allergen sensitization. Although component-resolved diagnostics have improved the characterization of fish allergy, comprehensive multicenter studies in children remain scarce.

The FASC study is a prospective, multicenter, observational study conducted in Spain to characterize children and adolescents with newly diagnosed IgE-mediated fish allergy. Consecutive eligible patients will be recruited in participating pediatric allergy units using standardized diagnostic and data collection procedures. Clinical information, allergy history, skin testing, serum specific IgE measurements, and molecular sensitization profiles will be collected. When clinically indicated, oral food challenges will be performed according to international recommendations and routine clinical practice.

The study aims to describe clinical phenotypes, molecular sensitization patterns, disease severity, quality of life, and geographical variability across Spain. The findings are expected to improve the understanding of pediatric fish allergy, support the identification of clinically relevant sensitization profiles, and contribute to more accurate diagnosis and individualized patient management.

Study Type

Observational

Enrollment (Estimated)

120

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

Accepts Healthy Volunteers

Sampling Method

Non-Probability Sample

Study Population

The study population consists of children and adolescents evaluated for suspected fish allergy in the Allergy Units of participating hospitals across Spain. Participants will be recruited consecutively from routine clinical practice at tertiary referral centers that are members of the Spanish Society of Allergy and Clinical Immunology (SEAIC). The study includes patients from multiple geographical regions, providing a representative sample of the Spanish pediatric population referred for specialized allergy assessment.

Description

Inclusion Criteria:

Children and adolescents aged 0 to 17 years (up to 18 years of age).
First clinical episode compatible with IgE-mediated fish allergy.
Evidence of allergic sensitization demonstrated by at least one of the following:
Positive skin prick test (wheal diameter ≥3 mm compared with the negative control); or
Serum specific IgE ≥0.35 kUA/L to at least one fish species or fish allergen component.
Written informed consent obtained from the parent(s) or legal guardian(s), and assent from participants aged 12 years or older, when applicable.

Exclusion Criteria:

Age ≥18 years.
Non-IgE-mediated fish allergy (e.g., fish-induced FPIES).
Severe dermographism, chronic urticaria, or severe atopic dermatitis preventing reliable interpretation of skin prick testing.
Inability to complete the diagnostic procedures required by the study.
Absence of informed consent or, when applicable, participant assent.

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of sensitization to clinically relevant fish allergen components. Time Frame: Baseline (Day 1)	Distribution of molecular sensitization profiles to clinically relevant fish allergen components and allergenic protein families in children and adolescents with newly diagnosed IgE-mediated fish allergy, as determined by component-resolved diagnostics performed at study enrollment.	Baseline (Day 1)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitization to individual fish allergen components Time Frame: Baseline (Day 1)	Frequency and distribution of sensitization to individual fish allergen components and allergenic protein families measured by component-resolved diagnostics.	Baseline (Day 1)
Specific IgE sensitization profile Time Frame: Baseline (Day 1)	Serum specific IgE sensitization to fish species and allergenic components determined using standardized laboratory methods.	Baseline (Day 1)
Oral food challenge outcome Time Frame: During the diagnostic evaluation (up to 3 months after baseline (Day 1))	Results of oral food challenges, including confirmation of clinical allergy and identification of tolerated fish species, when clinically indicated.	During the diagnostic evaluation (up to 3 months after baseline (Day 1))
Health-related quality of life Time Frame: Baseline (Day 1) and at completion of the diagnostic evaluation (up to 3 months after baseline (Day 1))	Health-related quality of life assessed using validated food allergy-specific quality-of-life questionnaires.	Baseline (Day 1) and at completion of the diagnostic evaluation (up to 3 months after baseline (Day 1))
Geographical variability in sensitization profiles Time Frame: Through study completion, an average of 18 months	Comparison of molecular sensitization profiles and clinical characteristics across participating regions in Spain.	Through study completion, an average of 18 months

Collaborators and Investigators

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

Sponsor

Carmelo Escudero

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

December 30, 2027

Study Completion (Estimated)

June 30, 2028

Study Registration Dates

First Submitted

July 18, 2026

First Submitted That Met QC Criteria

July 22, 2026

First Posted (Actual)

July 27, 2026

Study Record Updates

Last Update Posted (Actual)