Global research trends in the epidemiology of allergic disorders: a bibliometric and evidence-mapping review.

Introduction: Allergic diseases are highly prevalent worldwide and contribute substantially to morbidity and health-system burden. Bibliometric and evidence-mapping approaches can provide a comprehensive overview of research productivity, collaboration patterns, thematic structure, and distribution of evidence across epidemiologic domains, thereby identifying critical knowledge gaps. This study aimed to characterize global research trends in the epidemiology of allergic disorders from 2016 to 2025 using bibliometric and science-mapping techniques, complemented by evidence mapping. Methods: We analyzed 1,543 publications indexed in the Web of Science Core Collection and Scopus using Bibliometrix/biblioshiny and VOSviewer to evaluate publication growth, leading journals, authors, countries, collaboration networks, and thematic evolution based on keyword co-occurrence and mapping. An evidence-mapping framework was applied to quantify the distribution of research allergic phenotypes and epidemiologic fields including prevalence, incidence, burden of disease, risk factors, and outcomes. Results: Scientific production increased steadily (annual growth rate 7.59%), with clear acceleration after 2020, reflecting growing research prioritization of allergic diseases. Scientific production was concentrated within a small group of leading countries, most notably the United States and China, whereas international collaboration remained largely confined to established regional networks rather than broadly distributed global partnerships. Keyword and thematic analyses demonstrated an asthma-centered research structure, with strong emphasis on pediatric populations, prevalence, and risk-factor studies. Evidence mapping revealed a markedly uneven distribution of the literature: risk-factor research dominated across all phenotypes (83-89%), whereas burden-of-disease studies were consistently scarce (<7% across all conditions). Asthma accounted for the largest evidence base across all domains, while non-asthma conditions, including food allergy, anaphylaxis, urticaria/angioedema, and eosinophilic esophagitis, showed comparatively limited and fragmented coverage, particularly for incidence, burden, and patient-centered outcomes. Conclusion: Global allergy epidemiology research has expanded substantially over the past decade but remains geographically concentrated and structurally imbalanced. The field is heavily centered on asthma and risk-factor research, while critical gaps persist in burden estimation, incidence data, and outcome-focused studies for several allergic phenotypes. Addressing these disparities through broader geographic inclusion and more balanced epidemiologic investigation will be essential to improve the completeness, comparability, and policy relevance of global allergy research.