AbstractBackgroundEosinophilia is a common, hematologic abnormality detected in periodic health checkups with diverse etiologies. There are a few clinical practice guidelines for the management of eosinophilia.ObjectivesTo determine the prevalence of eosinophilia among patients undergoing periodic health examinations, evaluate its management and outcomes, and identify its associated factors.MethodsWe conducted a retrospective study that included patients with eosinophilia diagnosed during the 2018 periodic health examinations at Songklanagarind Hospital.ResultsThe prevalence rate of eosinophilia was 9.6% (988/10,299), and most patients (52.6%) were male with a median age of 53.0 (42.0–61.0) years. Only 174 patients (17.6%) were diagnosed and further examined to identify the cause of eosinophilia; including an examination of medical history (18.4%), physical examination (93.1%), laboratory analysis (9.2%), and consultation with internists (14.9%). Empirical anthelmintic therapy was administered in 130 patients (74.7%), and 49.2% achieved resolution. The possible causes of eosinophilia were identified in 20.7% (204/988), the most common cause being atopic disease (51.5%). Patients with moderate-to-severe eosinophilia were significantly more likely to be diagnosed, undergo further laboratory tests, and proceed with consultations with internists (adjusted OR [95% CI] = 3.52 [1.97–6.32], 17.13 [5.74–51.11], and 6.38 [1.95–20.93], respectively).ConclusionsEosinophilia is commonly identified in periodic health examinations, and most primary physicians lack knowledge regarding the diagnostic work-up required to determine the cause of eosinophilia. Empirical anthelmintic therapy showed satisfactory efficacy for the management of eosinophilia in areas where parasite infection is endemic.