The purpose of this study is to address the differential diagnosis of peripheral eosinophilia briefly. In this way, we concentrate on targeting atopic disease immunotherapy and their effect on absolute peripheral eosinophil counts and the application, as an indicator of treatment response, of peripheral eosinophil. Higher absolute numbers of peripheral eosinophils are usually correlated with better effects in atopic diseases. Many new eosinophil data as a biomarker comes from post-hoc immunotherapy analyses. While the main focus of certain trials was not due to improvements in eosinophilia, such trends have been seen. Benrizumab and AK002 cytolytic mAbs reduce eosinophil numbers of peripherals and tissues. Despite the therapeutic effectiveness found, dupilumab may have paradoxical intermittent eosinophilia.

The multiple cytokines that influence activation, proliferation, differentiation and survival of eosinophils are primarily a cause of complex atopic inflammation. This shows the challenges of using eosinophilia alone as a biomarker for the activity of atopic diseases. More focus should be paid to the effects of eosinophilic reactions by various methods of immunotherapy.