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Causes of low white blood cells

by Alivia Nyhan
Published: Last Updated on

Blood is made up of cells produced by the bone marrow that perform essential functions for the body to function correctly. Among the blood components, we find red blood cells, which carry oxygen throughout the body, platelets, which help fight bleeding through blood clotting, and white blood cells, also known as leukocytes, which help the body detect and kill bacteria and viruses to prevent disease.

Being part of the immune system, white blood cells are essential for the body’s health: they are our defenses! In addition to being present in the blood, they are also produced in the lymphatic system so that we can find them in the tonsils, spleen, adenoids, lymph nodes, and lymph, all parts of the body responsible for fighting diseases. Due to the critical function of leukocytes, any alteration in their values ​​can compromise our health.

We invite you to continue reading carefully this article by FastlyHealwhere we explain the leading causes of low white blood cells, medically known as leukopenia, its symptoms, and its relationship with some types of cancer.

Low white blood cells or leukopenia

A low count of white blood cells or leukocytes in the blood is known as leukopenia, which, as we explained earlier, are cells that help the body and the immune system fight disease. There are different types of white blood cells, and depending on the leukocyte is deficient, we can talk about :

  • Neutropenia: low levels of neutrophils.
  • Lymphopenia: low levels of lymphocytes.
  • Monocytopenia: low levels of monocytes.
  • Eosionopenia: low levels of eosinophils.
  • Basopenia: low levels of basophils.

The terms leukopenia and neutropenia are often used to refer to low white blood cells since neutrophils are the most critical type of leukocyte, as they are responsible for fighting infections in the body. In general, leukopenia is a condition that warns of another disease or that occurs due to cancer and the treatments suggested by this disease, such as chemotherapy.

When the leukopenia is mild, 1000 neutrophils per microliter of blood generally do not represent problems. The person improves frequently and recovers quickly from this condition’s symptoms, which we will explain later. However, when the leukopenia is severe, that is, there are 500 neutrophils or less for each microliter of blood, the person can considerably compromise their health since the body cannot find a way to defend itself against any bacteria, even in these In some cases, even germs that generally inhabit the mucous membranes of the body may pose a greater risk of infection.

Causes of low white blood cells

Many are the pathologies related to a low level of white blood cells. Here we explain the most common:

Bone marrow damage

Chemical treatments such as chemotherapy, exposure to radiation therapy, toxic substances, and some medicines can directly affect the production of blood cells in the bone marrow, decreasing the numbers of white blood cells, red blood cells, and platelets in the blood.

Bone marrow disorders

It occurs when the marrow does not produce enough white blood cells or produces too much of one type of white blood cell, resulting in a deficiency of the other white blood cells. The pathologies that can cause this are leukemia, myelodysplastic syndrome, myelofibrosis, myeloproliferative syndrome, and vitamin B12 or folate deficiency.


Some types of cancer can spread to the bone marrow and cause leukopenia. This is common in lymphomas.

Dangerous infections

When an infection is fatal, it immediately compromises the concentration of white blood cells causing leukopenia. This often occurs with septicemia, and in these cases, an emergency transfusion is necessary.

Autoimmune disorder

It occurs when the body mistakenly considers white blood cells to be a foreign body that poses a threat to health and ends up destroying them. This type of disorder occurs when the person has systemic lupus primates.


It occurs when the spleen grows excessively and destroys blood cells, which can cause anemia and leukopenia.

Some diseases

Thyroid disorders, parasite infections, rheumatoid arthritis, vitamin deficiency, copper and zinc deficiency, HIV, malaria, flu, dengue, and tuberculosis can lead to low white blood cells.


When an infection occurs in the body, white blood cells travel in large numbers to the blood vessels to explore and fight the disease. At this point, if the bone marrow is still producing blood cells, the white blood cell count appears low, although it is not.


The consumption of some medicines can interfere with the concentration of blood cells and cause leukopenia. Among the most common, we find clozapine, sodium valproate, lamotrigine (antiepileptic drugs), immunosuppressive drugs for transplant patients, and interferons to control multiple sclerosis. Some medications to control tobacco addiction and treat depression also often cause leukopenia. Consuming penicillin also lowers white blood cells.

Symptoms of leukopenia

Low white blood cells usually do not cause any symptoms. Some people with leukopenia experience weakness, fatigue, dizziness, or loss of appetite; however, symptoms are usually caused by the condition that triggers low white blood cells. However, when leukopenia is chronic and the situation has worsened, the person may manifest another series of conditions that are related to the low concentration of white blood cells in the blood; some of them are:

Common infections

Infections that attack the body very suddenly are a common symptom of leukopenia. Among these conditions, the most common are those that occur in the oral cavity, such as the appearance of canker sores, gum diseases such as gingivitis and periodontitis, and more frequent pathologies such as tonsillitis. Lung infections can also be a symptom of low white blood cells, bronchitis, and pneumonia are the most common. A prevalent and sometimes silent type of infection takes place in the urinary tract.


Anemia is a pathology that depends on the number of blood cells in the blood beyond the level of iron or hemoglobin. In some cases, anemia is diagnosed due to decreased hemoglobin and red blood cells, but some people may be anemic due to leukopenia.


Women may have heavier menstrual periods.

State of mind

Some people can affect their mental state by presenting irritability and moodiness or signs of neurasthenia (nervous exhaustion).

Treatment of low white blood cells

The treatment of leukopenia consists mainly in determining the cause of this condition to start treating the person, and as the disease is treated, the levels of white blood cells improve. However, sometimes many tests are necessary to find the root cause since disorders such as lupus or bone marrow diseases are not easy to diagnose.

Also, sometimes leukopenia results from a process that cannot be treated, such as low white blood cells from chemotherapy, some epilepsy drugs, or radiation therapy. In these cases, the person must take action to prevent infections and contact with bacteria since the white blood cells will not return to their average value until the end of said treatment.

Bone marrow suppression occurs when low levels of white blood cells are induced to destroy cancer cells in the bone marrow. In this process, nothing can be done to reverse leukopenia either. Often people who undergo this type of therapy need a bone marrow transplant to overcome leukopenia.

Whenever a drug is causing low levels of white blood cells, it is essential to consult with your doctor to see if there is another drug on the market that does not cause this side effect. One month after the change of medicine has been made, it is necessary to perform a blood test to check the level of white blood cells.

Living with leukopenia

If for a specific reason, there is no treatment for your type of leukopenia or the therapy, medication, or factor that is causing the white blood cells to below cannot be stopped, it is necessary to take actions to prevent the body from being infected with an infection or disease that could put health at risk. Taking these tips into account will be of great help to be healthy:

  • Use masks in public places, health centers, and whenever you contact people with diseases as familiar and straightforward as the flu. Any virus can be deadly.
  • Wash your hands several times a day with antibacterial soap to kill germs and bacteria.
  • Avoid contact with pets and all kinds of animals.
  • Set aside glass, plate, and cutlery for exclusive use.
  • Stay away from anyone with an infection.

This article is merely informative, at FastlyHeal .com we do not have the power to prescribe medical treatments or make any diagnosis. We invite you to see a doctor in the case of presenting any condition or discomfort.

If you want to read more articles similar to Causes of low white blood cells , we recommend that you enter our category of Blood, heart and circulation .

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