Anemia is a condition where you don’t have enough healthy red blood cells, to carry oxygen throughout your body. Anemia can be temporary or long term (chronic). In many cases, it’s mild, but anemia can also be serious and life-threatening.

Anemia can happen because:

  • Your body doesn’t make enough red blood cells.
  • Bleeding causes you to lose red blood cells more quickly than they can be replaced.
  • Your body destroys red blood cells.

Red blood cells carry oxygen throughout your body. When you don’t have enough red blood cells, your organs don’t get enough oxygen and can’t work properly. This can have severe consequences.

Types of anemia that can potentially be life-threatening include:

Aplastic anemia

Aplastic anemia is when your bone marrow becomes damaged, and your body therefore stops producing new blood cells. It can be sudden or get worse over time.

Common causes of aplastic anemia include

It can also have no known cause, which is referred to as idiopathic aplastic anemia.

Paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria is a rare, life-threatening disease. It causes blood clots, destroys blood cells, and impairs bone marrow function. It’s a genetic condition, usually diagnosed in people who are in their 30s or 40s.

Paroxysmal nocturnal hemoglobinuria is related to aplastic anemia. It often starts as aplastic anemia or arises after treatment for the condition.

Myelodysplastic syndromes

Myelodysplastic syndromes are a group of conditions that cause the blood-making cells in your bone marrow to become abnormal. Your bone marrow then doesn’t make enough cells, and the cells it does make are generally defective. These cells die earlier and are more likely to be destroyed by your immune system.

Myelodysplastic syndromes are considered a type of cancer. They may turn into acute myeloid leukemia, a type of blood cancer.

Hemolytic anemia

Hemolytic anemia is when your red blood cells are destroyed faster than your body can make them. It can be temporary or chronic.

Hemolytic anemia can also be inherited, which means it’s passed down through your genes, or acquired.

Potential causes of acquired hemolytic anemia include:

Sickle cell disease

Sickle cell disease is an inherited type of anemia. It causes your red blood cells to be deformed — they become sickle-shaped, rigid, and sticky. This causes them to get stuck in small blood vessels, which blocks blood flow throughout your body, depriving tissue of oxygen. It’s more common in people of African descent.

Sickle cell disease causes very painful episodes, swelling, and frequent infections.

Severe thalassemia

Thalassemia is an inherited condition in which your body doesn’t make enough hemoglobin. This is a protein that’s a crucial part of red blood cells. Without enough hemoglobin, your red blood cells don’t work properly and die more quickly than healthy cells.

Thalassemia can be mild or severe. It becomes severe if you inherit two copies of the gene that causes it.

Malarial anemia

Malarial anemia is a main symptom of severe malaria. Many factors contribute to its development, including:

Fanconi anemia

Fanconi anemia (FA) is a genetic condition that impairs bone marrow and causes you to have a lower than normal amount of all types of blood cells.

It often also causes physical abnormalities, such as malformed thumbs or forearms, skeletal abnormalities, a malformed or missing kidney, gastrointestinal abnormalities, infertility, and vision and hearing problems.

Fanconi anemia can also cause an increased risk of leukemia, as well as head, neck, skin, reproductive, and gastrointestinal cancers.

Common symptoms of anemia include:

You may also have symptoms specific to the condition underlying anemia.

Anemia happens when your body doesn’t make enough blood cells, your body destroys your red blood cells, or the red blood cells it does make are malformed.

Different causes of these conditions include:

Genetics

These are conditions that cause anemia and are inherited, which means they are passed down through one or both parents through your genes.

  • sickle cell
  • thalassemia
  • some hemolytic anemias
  • Fanconi anemia
  • paroxysmal nocturnal hemoglobinuria

Bleeding

Severe bleeding can cause sudden, short-term anemia. For example, this might happen after a traumatic injury where you lose a lot of blood.

Cancer

Cancers of the blood, lymphatic system, and bone marrow can cause anemia. Examples include:

  • aplastic anemia
  • some hemolytic anemias
  • myelodysplastic syndromes

Diseases

Acquired diseases, including malaria, can cause anemia. Other infections can cause aplastic anemia or hemolytic anemia. Autoimmune diseases are also a potential cause of anemia, as they may cause your body to attack red blood cells.

First, your doctor will take your family and medical history. Then they will do a physical exam to look for symptoms of anemia. After that, your doctor will draw blood for several tests. The most common are:

  • complete blood count to count the number of red blood cells and the amount of hemoglobin in your blood
  • tests to look at the size and shape of your red blood cells

Once you’re diagnosed with anemia, your doctor may do more testing to see if they can find the underlying cause of anemia. For example, they might do a bone marrow test to see how well your body makes red blood cells, look for internal bleeding, or scan for tumors.

Treating severe anemia takes more than just diet and lifestyle changes, although eating a healthy diet with lots of iron can help keep you healthy.

Sometimes, treating anemia requires treating the underlying cause. Examples include:

  • chemotherapy for myelodysplastic syndrome
  • eculizumab (Soliris) for paroxysmal nocturnal hemoglobinuria, which keeps your body from destroying red blood cells
  • immunosuppressants for some types of aplastic anemia and hemolytic anemias

In all types of anemia, blood transfusions can help replace your lost or defective red blood cells and reduce symptoms. However, it usually does not address the underlying cause.

A bone marrow transplant, also known as a stem cell transplant, is an option if you can’t make healthy red blood cells. In this procedure, your bone marrow is replaced with donor marrow that can make healthy cells.

This is the only cure for some type of anemia, such as paroxysmal nocturnal hemoglobinuria.

Anemia in general causes 1.7 deaths per 100,000 people in the United States annually. It is usually treatable if caught quickly, although some types are chronic, which means they need continual treatment.

The outlook for people with serious anemia will depend on the cause:

  • Aplastic anemia. People who are younger than 40 years old with severe aplastic anemia are usually treated with a bone marrow transplant. This can cure aplastic anemia. People over 40 years old, or for whom there’s not a good bone marrow match, are usually treated with medications. These can reduce symptoms but aren’t a cure. Up to 50 percent of patients treated with drug therapy have their aplastic anemia return, or develop another, related blood disorder.
  • Paroxysmal nocturnal hemoglobinuria. The median survival time after diagnosis of PNH is 10 years. However, new treatments can help people with this condition live to a normal life expectancy.
  • Myelodysplastic syndromes. Without treatment, the median survival time for myelodysplastic syndromes range from less than a year to approximately 12 years, depending on factors such as number of chromosome abnormalities and level of red blood cells. However, treatment is often successful, especially for certain types of this condition.
  • Hemolytic anemias. The outlook for hemolytic anemias depends on the underlying cause. Hemolytic anemia itself is rarely fatal, especially if treated early and properly, but the underlying conditions can be.
  • Sickle cell disease. Sickle cell disease decreases life expectancy, although people with this condition are now living into their 50s and beyond, due to new treatments.
  • Severe thalassemia. Severe thalassemia can cause death due to heart complications before age 30. Treatment with regular blood transfusions and therapy to remove excess iron from your blood can help the prognosis.
  • Malarial anemia. If diagnosed and treated quickly, malaria is usually curable. However, severe malaria, which is what causes anemia, is a medical emergency. The mortality rate for severe malaria varies widely, from 1.3 to more than 50 percent, depending on factors such as age, location, other presenting conditions, and overall health.
  • Fanconi anemia. A bone marrow transplant can cure severe FA. However, you would still have an increased risk of squamous cell carcinoma. Your prognosis also depends on your specific genetic abnormality that led to FA.