**__Noninfectious__**

Dietary supplements or medications: e.g., nonsteroidal antiinflammatory drugs, β‐lactam antibiotic drugs, or nitrofurantoin

Hematologic or neoplastic disease: lymphoma, eosinophilic leukemia, masto‐ cytosis, or solid tumors such as adenocarcinoma of the bowel or lung

Asthma or allergic disease: e.g., atopic dermatitis, allergic rhinitis, or eosino‐ philic esophagitis

Rheumatologic or connective‐tissue disease: eosinophilic granulomatosis with polyangiitis, sarcoidosis, or 

inflammatory bowel disease

Immunologic disease or immunodeficiency: Omenn’s syndrome, Job’s syndrome, or graft‐versus‐host disease
Hypereosinophilic syndrome: myeloid, lymphocytic, overlap, associated, familial, or idiopathic

Other causes: adrenal insufficiency, radiation exposure, or cholesterol emboli

**__Infectious__**

Fungal infection: coccidioidomycosis, allergic bronchopulmonary aspergillosis, paracoccidioidomycosis (less common), or histoplasmosis

Bacterial or mycobacterial infection: bartonellosis, syphilis, scarlet fever, or tuberculosis

Viral infection: human immunodeficiency virus infection or infection with human T‐lymphotropic virus type 1

Parasitic infection: protozoan infection (cystoisospora infection, sarcocystis, or Dientamoeba fragilis infection), ectoparasitic infection (scabies or myia‐ sis [rare]), or helminthic infection