2019 Volume 70 Issue 5 Pages 326-333
Eosinophils are multifunctional leukocytes involved in the etiology of inflammatory reactions in various organs. Eosinophilic respiratory diseases comprise diverse ailments presenting with tissue or peripheral eosinophilia. Primary eosinophilic respiratory diseases include simple pulmonary eosinophilia, acute eosinophilic pneumonia, chronic eosinophilic pneumonia, hypereosinophilic syndrome, and eosinophilic bronchitis. Eosinophilia can occur as a secondary condition in patients with allergic bronchopulmonary aspergillosis, bronchocentric granulomatosis, parasitic infection, or fungal infection, or as an adverse reaction to drugs or toxins. Furthermore, eosinophilia sometimes may occur in patients with vasculitis such as allergic granulomatosis. Asthma is a common comorbidity and a possible prerequisite condition for diagnosing eosinophilia. Although mild eosinophilia is sometimes associated with other respiratory diseases (e.g., lung cancer, pulmonary fibrosis, and mycobacterial infection), its association with such respiratory diseases is insignificant and does not affect disease progression. Thus, these respiratory diseases are not generally regarded as eosinophilic lung diseases. This study presents an overview of the characteristic clinical, histological, and radiological findings of various eosinophilic respiratory diseases.
