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Aplastic Anemia

Also called: acquired aplastic anemia, idiopathic aplastic anemia

What is aplastic anemia?

Aplastic anemia is a type of bone marrow failure. In aplastic anemia, the bone marrow’s stem cells do not make enough new blood cells. Most often, all three types of blood cells are affected (called pancytopenia):

  • Red blood cells, which carry oxygen (anemia)
  • White blood cells, which fight infections (neutropenia)
  • Platelets, which help the blood to clot and stop bleeding (thrombocytopenia)

Although aplastic anemia affects how many blood cells the body produces, the few that do mature and enter the bloodstream are normal.

Aplastic anemia is linked to some cancers and cancer treatments, but it is not a type of cancer.

Severe aplastic anemia is linked to a high risk of severe infections. If untreated, a person with this disorder can die of infection or bleeding.

What are the symptoms of aplastic anemia?

Symptoms of aplastic anemia are caused by decreased blood production. These include:


  • Feeling tired or dizzy
  • Shortness of breath
  • Rapid or irregular heartbeat
  • Pale skin
  • Headache


  • Unexplained or easy bruising or red/purple dots (petechiae)
  • Nosebleeds and bleeding gums
  • Bleeding that isn’t easily stopped, even when the cut is small


  • Frequent fevers
  • Frequent infections that last a long time
  • Mouth ulcers

How common is aplastic anemia?

Aplastic anemia is a rare disease that occurs in only one to two people per million each year. That’s 300 to 600 new cases across all age groups in the U.S.

What causes aplastic anemia?

In most aplastic anemia cases, the cause is unknown. Some believe the immune system (T cells) doesn't work right and attacks a person’s own bone marrow.

In some patients, aplastic anemia is linked to:

  • Exposure to toxic chemicals, drugs or radiation
  • Viral infections such as hepatitis, Epstein-Barr virus (EBV) or human immunodeficiency virus (HIV) 
  • Inherited bone marrow failure syndromes such as Fanconi anemia or dyskeratosis congenita. These syndromes can show up as bone marrow failure that is similar to aplastic anemia (but is actually another disease).

How is aplastic anemia diagnosed?

Aplastic anemia is diagnosed through a detailed medical and family history, plus a number of lab tests.

  • Complete blood count (CBC) with reticulocytes
    A small sample of blood is taken from the child’s vein and the cells are counted. Most patients have severe aplastic anemia, which means reticulocytes (immature blood cells), hemoglobin (red blood cells), platelets, and neutrophils are in very low numbers.
  • Bone marrow aspiration and biopsy
    The child is usually given anesthesia, to fall asleep and make the procedure painless. A needle is put into a bone in the hip (or lower leg in very young children) to remove a small amount of bone marrow. In patients with severe aplastic anemia, the bone marrow has very low cell content (hypocellular).
  • Other testing  
    Other special blood tests are used to diagnose aplastic anemia. These are a chromosomal breakage test, telomere length measurement, and analysis of PNH clones in blood. Sometimes, genetic testing is needed to rule out conditions that are passed through families.

How is aplastic anemia treated?

Treatment for aplastic anemia may include blood transfusions, medicines that inhibit the immune system and stem cell/bone marrow transplants.

Blood transfusion
Healthy red blood cells or platelets from one person are given to another person. Transfusions are given when hemoglobin or platelets fall below a critical number. Transfusions can relieve symptoms but do not treat causes of the disease.

Supportive medication
Patients with aplastic anemia have very low white blood cells and are at a very high risk for life-threatening infections. To treat or reduce infection risk, drugs are given to kill bacteria (antibiotics), viruses (antivirals) and fungi (antifungals).

Immunosuppressive therapy
Two drugs are often given to suppress the malfunctioning immune system. These drugs are anthithymocyte globulin (ATG) and cyclosporine. Some centers also give eltrombopag to boost stem cell production. This kind of therapy can last for up to two years.

Bone marrow transplant
A patient’s unhealthy or missing bone marrow is replaced with healthy cells from a donor, such as a family member or a matched unrelated donor. This is called an allogeneic bone marrow transplant. A bone marrow transplant can cure aplastic anemia for life.

Some patients may get side effects such as an immune system reaction against the body (graft-versus-host disease), severe infections during the transplant or rejection of donor cells. The long-term overall survival after transplant in children with aplastic anemia is over 90%.

If a patient has a matched sibling donor, a bone marrow transplant is used as a first-line therapy.

If a patient does not have a sibling donor, immunosuppressive therapy is used. But, recent studies show that a transplant from a matched unrelated donor (MUD), or mismatched family donor (haplotransplant) shows excellent success rates. Long-term outcomes are at least as good as immunosuppressive therapy.

St. Jude is conducting a clinical trial  to find out which therapy is better for patients.

Learn more about what to expect during a bone marrow transplant

What are the survival rates for aplastic anemia?

Aplastic anemia is a life-threatening condition with very high death rates (about 70% within 1 year) if untreated. The overall five-year survival rate is about 80% for patients under age 20. In recent years, the long-term outcomes of aplastic anemia patients have been continuously improving.

What are the complications of aplastic anemia?

Complications of aplastic anemia include severe life-threatening infections from bacteria or fungus. Other problems can arise from thrombocytopenia (bleeding risk) and anemia (weakness, heart failure).

Late complications may include relapse, paroxysmal nocturnal hemoglobinuria (PNH) or myelodysplastic syndrome (MDS), which is very rare.

How will aplastic anemia affect my child’s life?

Children with aplastic anemia need to be monitored closely. They need to stay in a hospital for treatment (bone marrow transplant or immunosuppressive therapy) and procedures (bone marrow analysis, central venous line placement). They also need regular clinic visits with blood draws and physical exams.

After discharge from the hospital, many patients visit the clinic 2–3 times per week. If drugs are given to suppress the immune system, treatment can last more than a year. This can differ based on the child’s response and other treatment options (i.e. If a bone marrow transplant donor becomes available).

Most children with aplastic anemia cannot attend school in a traditional setting. This is due to high infection risk and the need to visit the hospital frequently.

When should I call my doctor?

Call the doctor if your child has:

  • Fever
  • Bleeding
  • Signs of worsening anemia

Why choose St. Jude for your child’s aplastic anemia treatment?

  • St. Jude has a team of renowned experts who specialize in bone marrow failure and MDS. These experts work with other specialists around the world.
  • The nurse-to-patient ratio at St. Jude is unmatched — averaging 1:3 in hematology and oncology, and 1:1 in the Intensive Care Unit.
  • St. Jude offers your family the support needed to address physical, emotional, psychological, educational and other challenges to manage your child’s blood disorder.  
  • To improve outcomes and reduce side effects linked to transplant, doctors in the St. Jude Transplant Program work closely with scientists to rapidly move discoveries from the lab to the clinic.
  • St. Jude doctors are engaged in the latest research studies. Patients have the choice to take part when studies are available. By performing these studies, we hope to better understand and treat blood disorders. 

Associated Clinical Trials

TransIT: Unrelated Donor Transplant Versus Immune Therapy in Pediatric Severe Aplastic Anemia

  • St. Jude participates in this multi-center trial of the Northern American Pediatric Aplastic Anemia Consortium (NAPAAC)

INSIGHT-HD: Investigating the Genetics of Hematologic Diseases

  • This is a non-therapeutic research study for patients with bone marrow failure and other non-malignant blood diseases.


The St. Jude website is designed for educational purposes only and is not engaged in rendering medical advice or professional services. The information provided through this site should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, you should consult your health care provider.