IgE, Skin Prick Test Show Limited Diagnostic Utility for Pediatric Shrimp Allergy

New research is shedding light on the diagnostic utility of IgE and skin prick test (SPT) for identifying shrimp allergy in pediatric patients.1

Findings revealed SPT showed limited symptom correlation, whereas shrimp-specific IgE demonstrated greater diagnostic value than tropomyosin-specific IgE. Of note, no IgE cutoff accurately predicted a successfully passed oral food challenge (OFC).1

In line with increasing consumption rates of fish and shellfish, the rates of allergic reactions to shellfish have also increased. Of note, most people do not outgrow shellfish allergies, with studies showing that just 46% of people allergic to shrimp outgrew their shrimp allergy in 10 years.2,3

“Although research indicates that shrimp-induced anaphylaxis occurs less frequently in children than in adults, limited clinical studies have specifically addressed the pediatric presentation of shrimp allergy,” Yuri Takaoka, MD, PhD, of the department of pediatrics at Osaka Habikino Medical Center in Japan, and colleagues wrote.1

To evaluate the diagnostic accuracy and safety of testing methods for shrimp allergy, investigators conducted an OFC for Japanese children with suspected shrimp allergy, adhering to a standardized multicenter protocol at Kinki Food Challenge Network facilities. Children 0-15 years of age whose parents or legal guardians provided informed consent were eligible for inclusion if they demonstrated elevated shrimp-specific IgE antibody levels or had a history of allergic symptoms following shrimp ingestion between 2019 and 2022. Exclusion criteria were poorly controlled allergic comorbidities, such as asthma and atopic dermatitis.1

Before the OFC, each participant underwent shrimp-, tropomyosin-, house dust mite–, and cockroach-specific IgE level measurements and SPT. During the OFC, children were administered boiled black tiger shrimp (Penaeus mondon) or white-leg shrimp (Litopenaeus vannamei) in portions of 2, 5, or 10 g every 30 minutes, totaling 17 g within 1 hour. Patients were then observed for a minimum of 2 hours post ingestion to assess for symptoms.1

Symptom severity was scored using the Anaphylaxis Scoring Aichi (ASCA) system. A positive OFC result, indicating persistent shrimp allergy, was defined by a total ASCA score ≥ 10 or by the presence of objective dermatologic symptoms.1

A total of 66 children underwent the OFC. The median age was 6 years and 64% of participants were male. All patients demonstrated house dust mite–specific IgE level > 0.35 IUA/mL and 16 were diagnosed with persistent shrimp allergy.1

OFC-negative patients were instructed to continue shrimp ingestion at home. Of these, 40 were confirmed as tolerant, exhibiting no symptoms upon repeated shrimp ingestion, while 8 experienced mild symptoms, leading to a diagnosis of mild shrimp allergy.1

Investigators noted median SPT wheal diameters in persistent, mild allergic, and tolerant groups were similarly elevated (8.5 vs 9.5 vs 8.0 mm; P = .99).1

Further analysis revealed patients with persistent shrimp allergy had greater median shrimp- and tropomyosin-specific IgE level than those classified as mild or tolerant (shrimp: 73.5 vs 30.0 vs 9.4 IUA/mL; P = .01; tropomyosin: 68.0 vs 41.9 vs 11.5 IUA/mL; P = .16). Additionally, receiver-operating characteristic analysis determined optimal IgE cutoff values as 58.2 IUA/mL for shrimp-specific IgE and 33.5 IUA/mL for tropomyosin-specific IgE.1

“Our findings identified optimal thresholds of 58.2 and 33.5 IUA/mL for shrimp- and tropomyosin-specific IgE, respectively, on the basis of ROC-curve analyses,” investigators concluded.1 “These updated thresholds can assist clinicians in establishing more accurate diagnoses for shrimp allergy.”

References

1. Takaoka Y, Tsurinaga Y, Hiraguchi Y, et al. Assessing diagnostic tests for shrimp allergy in children: A multicenter trial. Jaci Global. doi: 10.1016/j.jacig.2025.100471

2. Yehya NA. What you need to know about shellfish allergy diagnosis, treatment. UC Davis Health. October 6, 2022. Accessed May 9, 2025. https://health.ucdavis.edu/news/headlines/what-you-need-to-know-about-shellfish-allergy-diagnosis-treatment/2022/10

3. Giovannini M, Beken B, Buyuktiryaki B,et al. IgE-Mediated Shellfish Allergy in Children. Nutrients. doi:10.3390/nu15122714