What is agranulocytosis?

Agranulocytosis is a life-threatening blood disorder. It happens when the body doesn’t make enough of a type of white blood cells called neutrophils. White blood cells are part of the immune system. They protect the body from infection by fighting off germs that make us sick.

Also known as granulocytopenia, agranulocytosis is a severe form of neutropenia. Neutropenia is lower-than-normal levels of white blood cells. People with a low white blood cell count are very vulnerable to infection. They may get sick from germs that wouldn’t be harmful otherwise. Healthcare providers can treat agranulocytosis with medications. Untreated, the condition can lead to severe infections. It can even lead to sepsis (a severe reaction to infection) and death.

What are the types of agranulocytosis?

There are two types of agranulocytosis. It can be inherited (present at birth) or acquired.

  • Inherited agranulocytosis results from a genetic disorder. This problem affects how the body produces white blood cells. Infantile genetic agranulocytosis is a rare form of inherited agranulocytosis. It is also called Kostmann syndrome or congenital agranulocytosis. Newborns with this condition have recurring infections, fevers, inflammation and problems with their bones.
  • Acquired agranulocytosis can result from certain infections. Exposure to chemicals and some prescription medications may also cause it. Cancer-treating drugs and antipsychotic medications commonly cause acquired agranulocytosis. This form of the disorder is also called drug-induced agranulocytosis.

How common is agranulocytosis?

Agranulocytosis affects about seven people of every 1 million each year. It’s slightly more common in women. People of all ages can get the condition.

Inherited agranulocytosis is more common among babies and children. The acquired form appears more often in adults.

Agranulocytosis is more common among people who:

  • Are undergoing chemotherapy treatments for cancer.
  • Have autoimmune diseases such as lupus or rheumatoid arthritis.
  • Take certain prescription drugs, such as the antipsychotic medication clozapine (Clozaril®).

What causes agranulocytosis?

Granulocytes are white blood cells that are part of your immune system. These cells contain enzymes that kill germs and break down substances that may harm your body. There are three types of granulocytes: neutrophils, eosinophils and basophils.

Agranulocytosis happens when the levels of neutrophils are dangerously low. If you don’t have enough neutrophils, you’re at risk of frequent or chronic (long-term) infections. Your risk of severe infection increases over time if neutrophil levels remain low.

What causes acquired agranulocytosis?

Several types of prescription medications cause acquired agranulocytosis. Infections, other health conditions and exposure to chemicals can also lead to the disorder. Causes of agranulocytosis include:

  • Autoimmune disorders, including lupus and rheumatoid arthritis.
  • Bone marrow disease and bone marrow failure disorders like aplastic anemia.
  • Chemotherapy.
  • Exposure to toxins or chemicals, such as lead or mercury.
  • Infections such as malaria, tuberculosis and Rocky Mountain spotted fever.
  • Prescription drugs, including some antibiotics, antipsychotic medications and drugs to treat thyroid problems.
  • Poor nutrition and vitamin deficiencies.

What are the symptoms of agranulocytosis?

Agranulocytosis itself doesn’t have symptoms. People with the disorder have symptoms of infection. Signs of agranulocytosis may appear suddenly or gradually. They include:

  • Fever and chills.
  • Faster heart rate and breathing.
  • Sudden low blood pressure (hypotension), which can make you feel lightheaded or weak.
  • Muscle weakness and fatigue.
  • Sore mouth and throat and bleeding, inflamed gums.
  • Ulcers (sores) in the mouth and throat that make it difficult to swallow.

Last reviewed by a Cleveland Clinic medical professional on 11/25/2020.


  • Merck Manuals. Neutropenia. Accessed 12/7/2020.
  • National Organization for Rare Disorders. Agranulocytosis, Acquired. Accessed 12/7/2020.
  • Sedhai YR, Lamichhane A, Gupta V. Agranulocytosis. [Updated 2020 Jun 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan. Accessed 12/7/2020.

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