Cytopenia occurs when one or more of your blood cell types is lower than it should be.

Your blood consists of three main parts. Red blood cells, also called erythrocytes, carry oxygen and nutrients around your body. White blood cells, or leukocytes, fight infection and battle unhealthy bacteria. Platelets are essential for clotting. If any of these elements are below typical levels, you may have cytopenia.

Several types of cytopenia exist. Each type is determined by what part of your blood is low or decreased.

  • Anemia occurs when your red blood cells are low.
  • Leukopenia is a low level of white blood cells.
  • Thrombocytopenia is a deficiency of platelets.
  • Pancytopenia is a deficiency of all three parts of the blood.

The possible causes of cytopenia are complex and varied. Among these causes are peripheral destruction, infections, and side effects of medication. Two types of cytopenia that are related to the underlying cause of the low blood cell count are autoimmune cytopenia and refractory cytopenia.

Autoimmune cytopenia

Autoimmune cytopenia is caused by an autoimmune disease. Your body produces antibodies that fight against your healthy blood cells, destroying them and preventing you from having adequate blood cell counts.

Refractory cytopenia

Refractory cytopenia occurs when your bone marrow does not produce mature, healthy blood cells. This may be the result of a group of cancers, such as leukemia or another bone marrow condition. Several types of refractory cytopenia exist. According to the American Cancer Society, they are defined by how the blood and the bone marrow look under the microscope.

The symptoms of cytopenia depend on which type of the condition you have. They can also depend on the underlying problem or condition that’s causing the low blood cell counts.

Symptoms of anemia include:

  • fatigue
  • weakness
  • shortness of breath
  • poor concentration
  • dizziness or feeling lightheaded
  • cold hands and feet

Symptoms of leukopenia include:

  • frequent infections
  • fever

Symptoms of thrombocytopenia include:

  • bleeding and bruising easily
  • difficulty with stopping bleeding
  • internal bleeding

Refractory cytopenia may cause few symptoms in the early stages. As the blood cell counts fall, symptoms such as shortness of breath, frequent infections, fatigue, and easy or free bleeding may occur. In the case of refractory cytopenia, it’s possible the low blood cell counts will lead doctors to an underlying problem like cancer or leukemia.

Cytopenia caused by an autoimmune response may occur with other systemic symptoms that mimic those of other types of cytopenia. These symptoms include:

  • fatigue
  • weakness
  • frequent infections
  • fever
  • bleeding and bruising easily

If you’re experiencing unusually low blood cell counts, your doctor will look for an underlying cause to explain the numbers. Each type of cytopenia can be caused by several different and unique conditions.

Causes of anemia include:

  • low iron levels
  • frequent bleeding
  • destruction of cells while in circulation within your body
  • abnormal red blood cell production from the bone marrow

Causes of leukopenia include:

  • chronic infection, such as HIV or hepatitis
  • cancer
  • autoimmune disease
  • cancer treatments, including radiation and chemotherapy

Causes of thrombocytopenia include:

  • cancer
  • chronic liver disease
  • cancer treatments, including radiation and chemotherapy
  • medications

In some people with cytopenia, doctors are unable to find an underlying cause. In fact, doctors are unable to find a cause in about half of people with pancytopenia. When a cause is not known, it’s called idiopathic cytopenia.

As you can see from the list of potential causes, cytopenia is often associated with cancer and leukemia. That’s because both of these diseases destroy the healthy blood cells in your body. They can also destroy your bone marrow. The formation and development of blood cells takes place in your bone marrow. Any damage to this spongy tissue inside your bones can impact your blood cells and your blood’s health.

Other conditions commonly associated with cytopenia include:

  • cancer, such as leukemia, multiple myeloma or Hodgkin’s or non-Hodgkin’s lymphoma
  • bone marrow disease
  • severe B-12 deficiency
  • chronic liver disease
  • autoimmune disease
  • viral infections, including HIV, hepatitis, and malaria
  • blood diseases that destroy blood cells or prevent blood cell production, such as paroxysmal nocturnal hemoglobinuria and aplastic anemia

Cytopenia is diagnosed with a blood test called a complete blood count (CBC). A CBC shows white blood cell, red blood cell, and platelet counts. To conduct a CBC, your doctor or a nurse will draw blood and send it to a lab for analysis. A CBC is a very common blood test, and your doctor may discover cytopenia from the results without suspecting it. However, if your doctor suspects you have low blood cell counts, a CBC can confirm it.

If the results indicate low numbers for any part of your blood, your doctor may then order other tests to diagnose the underlying cause or look for potential explanations. A bone marrow biopsy and bone marrow aspiration can offer a detailed look at your bone marrow and blood cell production. These tests may be used to confirm or rule out bone marrow diseases or issues that may cause low blood cell counts.

Treatment for cytopenia depends on the cause.

For cytopenia caused by cancer or leukemia, treatment for these diseases can also treat low blood cells. However, many patients undergoing treatment for either of these diseases may experience lower blood cell counts as a result of the treatment.

Corticosteroids are often the first-line treatment for several types of cytopenia. Many patients respond well to the treatment. However, some may relapse or not respond at all. In that case, more aggressive treatment options may be used. These include:

  • immunosuppressive therapy
  • bone marrow transplant
  • blood transfusion
  • splenectomy

Once diagnosed, many people will be able to treat cytopenia and restore healthy blood cell counts. People with anemia, for example, may be able to boost their iron intake from foods such as red meat, shellfish, and legumes. That may restore your red blood cell count, and your doctor may routinely check your blood count to help you maintain healthy levels.

Some of the causes for cytopenia, however, require longer and more in-depth treatment. Those causes include cancer and leukemia, treatments for these conditions, and other serious conditions like bone marrow disease and aplastic anemia. For people diagnosed with serious underlying causes, the outlook often depends on the severity of the condition and how successful treatments are.