A short mnemonic for eosinophilia is CHINA:
- Connective tissue diseases, like eosinophilic granulomatosis with polyangiitis (aka Churg-Strauss) and rheumatoid arthritis
- Helminths, especially Strongyloides
- Idiopathic, which is simply called hypereosinophilic syndrome
- Neoplasms, like Hodgkin lymphoma, CML, and some solid-organ cancers
- Allergies etc, which includes asthma and drug-induced eosinophilia (don’t forget about DRESS)
- Also, Addison’s disease, for some reason
Of interest, helminth infections can cause a Loffler’s syndrome, also known as eosinophilic pneumonia, where you see a peripheral eosinophilia on the blood count and pulmonary infiltrates on the chest x-ray.
Read more: Eosinophils in Chapter 80: Disorders of Granulocytes and Monocytes, Harrison’s Principles of Internal Medicine 19e.