SHELLFISH allergy, particularly shrimp allergy (SA), is increasingly recognised as a significant public health concern, with rising prevalence worldwide. However, estimates of its true burden vary widely due to differences in study design and diagnostic methods, such as self-reported surveys, skin prick tests (SPT), specific IgE (sIgE) measurements, and oral food challenges. To address these discrepancies, a recent meta-analysis synthesised data from 40 studies across diverse regions and age groups, offering the most comprehensive overview of SA prevalence to date.
The pooled results revealed marked variation depending on the diagnostic approach: self-reported symptomatic SA was 1.90%, self-reported physician-diagnosed SA 1.94%, SPT- or sIgE-based prevalence 2.76%, probable SA (sensitisation plus clinical symptoms) 0.43%, and food challenge-confirmed SA just 0.50%. This stark difference highlights the risk of overestimation when relying solely on self-reported data, underlining the need for improved diagnostic accuracy.
Large-scale surveys, such as those conducted by the University of Chicago, align with these findings, reporting crustacean allergy prevalence of around 1.2%. Interestingly, the meta-analysis confirmed that SA is more common in adults than children, possibly due to cumulative exposure and sensitisation. Regional variation was also evident, with higher prevalence reported in Asia, where shrimp consumption is widespread, compared with lower levels in Europe and Africa. These differences may reflect dietary habits, genetic predisposition, and environmental exposures, though further research is needed.
Despite its strengths, the study noted high heterogeneity among prevalence estimates, influenced by cultural, geographic, and methodological factors. Self-reported data, while convenient, often exaggerates prevalence, whereas oral food challenge, the diagnostic gold standard, remains rarely feasible in large-scale research due to cost and ethical considerations.
The findings emphasise the importance of standardised diagnostic criteria to ensure consistency across studies and more accurate assessment of SA prevalence. Clinically, greater awareness of the gap between reported and confirmed allergies is needed to prevent unnecessary dietary restrictions and to ensure high-risk individuals have access to epinephrine auto-injectors. Looking forward, prospective cohort studies and investigations into genetic and environmental influences will be critical to refining public health strategies and improving patient outcomes.
Reference
Chen J et al. Prevalence of shrimp allergy: a meta-analysis based on different diagnostic methods. Front Allergy. 2025;6:1635274.
