Introduction: Peripheral blood eosinophilia is observed in various diseases or conditions. However, information about eosinophilia in patients visiting a general hospital is limited. We investigated various angles with respect to cases involving eosinophilia. Methods: We retrospectively evaluated the patients with an eosinophil count ≥ 500/uL in their peripheral blood who visited our department during 6 years. Inquiry contents included age, sex, eosinophil count, leukocyte count, and the names of diseases presumed to be occasional. Result: A total of 1,044 cases were enrolled ; the median eosinophil and leukocyte counts were 673/uL (range: 502-18,860/uL) and 7,100/uL (range: 2,600-50,700/uL), respectively. The suspected causes of eosinophilia were infection in 308 (29.5%) , atopy/allergic disorder in 253 (24.2%), hypereosinophilia-associated disease (HEAD) in 33 (3.2%), neoplasm in 32 (3.1 %), autoimmune/autoinflammatory disease in 28 (2.7%), and others in 47 (4.5%) cases; the causes remained unknown in 343 cases (32.8%). The most frequent single cause was common cold (n = 110), followed by atopy (n = 80) , and human immunodeficiency virus (HIV) /acquired immunodeficiency syndrome (AIDS) (n = 65), whereas few cases were affected by parasitic infection (n = 3) . Discussion: Parasites are less, and atopy allergic diseases are more frequent causes, of eosinophilia in Japan, an industrialized nation, while non-allergic diseases caused many cases in this study. Our findings may supplement the traditional differential diagnosis of eosinophilia. Conclusion: Clinicians should consider not only atopy allergic disorders but non-allergic disorders such as infections or malignancies when confronted with eosinophilia of unknown origin.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract