Causes
Neutropenia can be caused by various factors, which can be broadly classified into the following categories:- Decreased production in the bone marrow:
- Congenital/Inherited disorders: Some people are born with conditions that affect neutrophil production, such as:
- Cyclic neutropenia
- Severe congenital neutropenia (Kostmann syndrome)
- Shwachman-Diamond syndrome
- Congenital/Inherited disorders: Some people are born with conditions that affect neutrophil production, such as:
- Acquired disorders: Conditions that damage the bone marrow or interfere with its function can lead to neutropenia:
- Aplastic anemia
- Myelodysplastic syndromes (MDS)
- Leukemia and other bone marrow cancers
- Myelofibrosis
- Vitamin deficiencies (e.g., B12, folate)
- Infections: Certain infections can temporarily suppress bone marrow function:
- Viral infections (e.g., HIV, Epstein-Barr virus)
- Bacterial infections (e.g., tuberculosis)
- Medications: Many drugs can cause neutropenia, including:
- Chemotherapy drugs
- Antipsychotic medications
- Anticonvulsants
- Antibiotics
- Immunosuppressants
- Exposure to toxins:
- Radiation therapy
- Certain chemicals (e.g., benzene)
- Increased destruction of neutrophils:
- Autoimmune disorders: In some conditions, the body's immune system mistakenly attacks and destroys neutrophils:
- Systemic lupus erythematosus (SLE)
- Rheumatoid arthritis
- Felty syndrome (a complication of rheumatoid arthritis)
- Splenomegaly: An enlarged spleen can trap and destroy neutrophils.
- Autoimmune disorders: In some conditions, the body's immune system mistakenly attacks and destroys neutrophils:
- Other causes:
- Severe infections: Overwhelming infections can consume neutrophils faster than they can be produced.
- Malnutrition: Severe malnutrition can impair bone marrow function.
Symptoms
Neutropenia itself does not usually cause specific symptoms. However, the increased risk of infections due to the low neutrophil count can lead to various symptoms, including:- Frequent infections
- Delayed wound healing
- Mouth sores (mucositis)
- Sore throat
- Fever
- Chills
- Pneumonia
- Sinusitis
- Skin infections
Diagnosis
Neutropenia is diagnosed through a blood test:- Complete blood count (CBC): This test measures the number of different types of blood cells, including neutrophils.
- The absolute neutrophil count (ANC) is calculated by multiplying the total white blood cell count by the percentage of neutrophils.
- An ANC of less than 1,000 cells/microliter is generally considered neutropenia. The lower the ANC, the higher the risk of infection.
- Peripheral blood smear: To examine the appearance of blood cells.
- Bone marrow biopsy: To assess the production of blood cells in the bone marrow.
- Blood tests: To check for infections, autoimmune disorders, and vitamin deficiencies.
Treatment
Treatment for neutropenia depends on the cause and severity:- Treatment of the underlying cause: Addressing the condition causing the neutropenia is crucial.
- Discontinuing or changing medications that are causing neutropenia.
- Treating infections with antibiotics, antifungals, or antivirals.
- Managing autoimmune disorders with immunosuppressive therapy.
- Treating bone marrow disorders (e.g., chemotherapy for leukemia, bone marrow transplantation for aplastic anemia).
- Growth factors:
- Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) are medications that stimulate the bone marrow to produce more neutrophils.
- Preventive measures:
- Good hygiene: Frequent handwashing and careful attention to personal hygiene can help reduce the risk of infection.
- Avoiding crowds and sick people: Limiting exposure to potential sources of infection.
- Prophylactic antibiotics or antifungals: In some cases, medications may be given to prevent infections.
- Dietary precautions: Following food safety guidelines to minimize the risk of foodborne infections.
- Blood transfusions: In some cases, blood transfusions may be necessary.
- Stem cell transplantation: For severe cases of neutropenia due to bone marrow failure.
Living With a Low Neutrophil Count
Most low neutrophil counts found on routine blood work are mild, stable, and harmless, and a smaller number are the first sign of something that needs urgent attention. Knowing which kind you have, and what to do about a fever, is what living with neutropenia comes down to.
The count that needs no treatment
A mildly low count that has been the same for years, with no history of unusual infections, is very often benign. People of African, Middle Eastern, or West Indian ancestry frequently carry an inherited variant that keeps the measured count below the standard range while immune function is entirely normal; this needs no workup beyond confirming it is stable. Our blood work explained article covers how the differential is read. A repeat count a few weeks later, ideally when you are well, sorts out the temporary dips that follow a viral illness.
The count that needs a call
A count that is falling on successive tests, a very low count, or one arriving with anemia or low platelets at the same time points toward the bone marrow and is evaluated promptly, sometimes with a marrow biopsy, because leukemia, lymphoma, and marrow failure present this way. Weight loss, night sweats, an enlarged spleen, or mouth ulcers that keep returning raise the same concern. Vitamin B12 and folate deficiency, an underactive thyroid, and HIV are checked because each is treatable.
Medications that lower the count
Methimazole, methotrexate, hydroxyurea, trimethoprim-sulfamethoxazole, clozapine, some seizure medications, and chemotherapy are the usual culprits, and the sudden severe drop methimazole or clozapine can cause typically announces itself with sore throat and fever in the first months. Anyone on those drugs gets a same-day blood count for fever rather than waiting it out. Autoimmune neutropenia in lupus or rheumatoid arthritis is treated by controlling the underlying disease.
Fever is the emergency
A severely low count removes the body's ability to wall off bacteria, so an infection can spread to the bloodstream within hours with few outward signs. A temperature of 100.4°F or higher, or chills and feeling unwell even without a measured fever, means an emergency department visit for blood cultures and intravenous antibiotics, not a call in the morning. People whose counts are expected to fall, such as during chemotherapy, are given filgrastim to shorten the low period, and some are given preventive antibiotics.
Everyday precautions in Florida
With a significantly low count, cuts and scrapes are cleaned at once, gardening is done in gloves, raw shellfish and undercooked meat are avoided, and open wounds stay out of the Gulf and bay; our Vibrio safety and gardener safety articles explain the local hazards. Inactivated vaccines including the annual flu shot are encouraged, while live vaccines are avoided during severe neutropenia. Our hematology team manages the evaluation and monitoring. The National Cancer Institute and the American Society of Hematology publish patient guidance on infection risk.
If a blood test showed a low white cell count and nobody explained what it means, schedule a visit.