Drugs

• Ganciclovir

• Zidovudine

• Trimethoprim-sulfamethoxazole

• Pentamidine

• Rifabutin

• Antineoplastic chemotherapy

• Dapsone

• Amphotericin B

• Ritonavir

• Delavirdine

• Nelfinavir

Deficiencies

• Folate

• Vitamin B₁₂

Infection

• Human immunodeficiency virus (HIV)

• Mycobacterium avium complex (MAC)

• Mycobacterium tuberculosis

• Histoplasma capsulatum

Neoplasia

• Non-Hodgkin’s lymphoma

• Multiple myeloma

Autoimmune neutropenia

Hypersplenism

• Infection

• Hemophagocytosis

• Cirrhosis