Appropriate Tests


Review clinical features, including history of exposure to drugs, toxins, or recent viral illness if isolated finding or features to suggest pancytopenia rather than isolated neutropenia as may be first manifestation of pancytopenia.

Full blood count, Blood film, White cell count differential, Bone marrow aspiration if significant and no diagnosis. Infective problems are uncommon unless the neutrophils are <1.0x109/L.

See also Febrile neutropenia, Immunodeficiency, Infection (increased susceptibility), Neutrophil dysfunction

Decreased production


Drug reactions


  • Predictable
    • Cytotoxic drugs
    • Alcohol

Usually pancytopenia, rather than isolated neutropenia.

  • Idiosyncratic
    • Antithyroid drugs
    • Chlorpromazine
    • NSAID
    • Sulphonamides
    • Clozapine
    • Gold


Bone marrow failure

  • Irradiation
  • Bone marrow infiltration
  • Acute leukaemia
  • Myelodysplasia
  • Lymphomas
  • Metastatic tumour

Bone marrow failure is usually associated with pancytopenia, rather than isolated neutropenia.

See also Pancytopenia

See Myelodysplastic syndromes

Megaloblastic anaemia

Usually pancytopenia, rather than isolated neutropenia.

Chronic idiopathic neutropenia



  • Chediak-Higashi syndrome
  • Diamond-Blackfan syndrome
  • Associated with inborn errors of metabolism eg, organic acidaemias.

See under Immunodeficiency

Increased destruction and/or margination


Immune, especially

  • SLE
  • Rheumatoid arthritis

Check relevant autoimmune serology profile.

Drug reactions (may be predictable and dose-related, as seen following cytotoxic chemotherapy, or an idiosyncratic reaction.

Examples include clozapine, penicillins.

Drug associated neutrophil antibodies.


  • Felty syndrome


Neutropenia, Splenomegaly and Rheumatoid arthritis. 





Decreased production and increased destruction


Viral infection

  • Infectious mononucleosis, CMV, Measles, Rubella
  • HIV infection
  • Dengue fever


See Cytomegalovirus infection

See Dengue

Bacterial infections

  • Septicaemia
  • Typhoid fever

The neutrophil count is variable in severe bacterial infection, but neutropenia is common, especially in neonates and in patients with Gram-negative septicaemia.

Protozoal infection

  • Malaria
  • Kala-azar
  • Trypanosomiasis


Hairy cell leukaemia


Neutropenia with an expansion of LGLs


Cyclic neutropenia

Follow-up Full blood count, White cell count differential over time, Flow cytometry.

Kostmann's Syndrome

Infantile genetic agranulocytosis

Felty Syndrome

Neutropenia, Splenomegaly and Rheumatoid arthritis. 

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