Severe aplastic anemia is a rare blood disorder where an autoimmune reaction leads to your bone marrow not producing enough blood cells.

Depending on the severity of aplastic anemia symptoms, doctors classify it as:

  • non-severe
  • severe
  • very severe

Newer treatments like bone marrow transplants and immunosuppressant medications have vastly increased survival rates and quality of life for people with severe aplastic anemia. People with untreated severe aplastic anemia tend to have very poor outlooks.

Researchers still don’t fully understand why aplastic anemia develops. It’s believed to be related to an autoimmune reaction against the cells in your bone marrow that produce blood cells.

Read on to learn more about this rare disorder, including symptoms, causes, and treatment options.

People with severe aplastic anemia have low levels of:

  • red blood cells
  • white blood cells
  • platelets

Most symptoms of aplastic anemia are related to low levels of these three types of blood cells.

Potential symptoms include:

In about two-thirds of cases, the cause of aplastic anemia isn’t known. When the underlying cause isn’t known, it’s called idiopathic aplastic anemia.

Researchers don’t fully understand why aplastic anemia develops, but it’s thought to be triggered by an autoimmune reaction where a type of white blood cell (a T-cell) attacks stem cells in your bone marrow that produce blood cells.

This autoimmune reaction may be triggered by a combination of genetics and environment.

About 70% of aplastic anemia cases are thought to be acquired, meaning they’re triggered by environmental factors like:

  • medications, such as some chemotherapy medications
  • toxic chemicals
  • viral infections like viral hepatitis

The remaining 30% of cases are thought to be hereditary, meaning they’re linked to genes passed through families.

The most common hereditary cause is Fanconi anemia. Fanconi anemia is usually a recessive disease caused by mutations in the FANC gene, but about 2% of cases develop from a gene mutation on the X chromosome. “Recessive” means you need an associated mutation from both parents to develop the disease.

Severe aplastic anemia can develop at any age, and it occurs in all sexes about equally. Some research reports a slightly higher occurrence in males.

It’s thought to affect about 1 in 430,000 people in Europe and the United States and about 3 times more people in East Asia.

Other potential risk factors include:

Severe aplastic anemia can lead to complications like:

Doctors use a variety of tests to diagnose aplastic anemia and rule out other blood conditions like leukemia or myelodysplastic syndrome.

Tests include:

Doctors can also use the results of these tests to determine the severity of your aplastic anemia. Factors that determine the severity of aplastic anemia include your:

  • number of functioning bone marrow stem cells
  • neutrophil (a type of white blood cell) count
  • platelet count
  • reticulocyte (immature red blood cell) count

In recent years, researchers have developed stem cell transplants as a potential cure for aplastic anemia. A stem cell transplant involves injecting stem cells from the bone marrow of a donor to replace your own stem cells.

Researchers have developed clearer treatment guidelines for severe aplastic anemia than non-severe.

The standard first-line therapy for a person with severe aplastic anemia is usually a stem cell transplant. The stem cells come from a genetically compatible donor. The donor is often a close relative, but it can also be a stranger.

If a suitable donor isn’t available for a bone marrow transplant or if you’re not a candidate, immunosuppressants are generally used as the primary treatment to stop the autoimmune reaction.

Immunosuppressants you might receive include:

  • equine antithymocyte globulin
  • cyclosporin A

It’s still not fully understood why these medications reduce symptoms in some people with aplastic anemia.

People who don’t respond to these medications might receive eltrombopag. This medication may also be combined with equine antithymocyte globulin or cyclosporin A.

The symptoms of aplastic anemia can be vague, especially in the early stages. But it’s important to see your doctor if you develop potential signs, such as:

  • unexplained weight loss
  • fatigue
  • bleeding or bruising
  • purple dots on your skin

Severe aplastic anemia may lead to rapid death if it’s untreated. More than 75% of people with aplastic anemia survive at least 5 years after receiving a bone marrow transplant from a suitable donor.

Aplastic anemia life expectancy with treatment

In a 2020 study, researchers examined the long-term survival of 302 people with anaplastic anemia treated with either a stem cell transplant or immunosuppressive therapy.

They found that 44% of people who received a stem cell transplant and 40% of people who received immunosuppressant therapy were alive 30 years later. The results were better in recent years.

The researchers also found that 96% of people who were still alive 25 years later were in complete remission at their last follow-up.

With treatment, many people with severe aplastic anemia are now able to live for many years in remission.

The symptoms of aplastic anemia can be vague in the early stages but tend to get worse over time. It’s important to reach out to a doctor if you develop concerning symptoms like atypical bleeding or bruising.