Anemia

What Is Anemia?

Anemia is a condition that happens when your blood doesn’t have enough healthy red blood cells or hemoglobin. Hemoglobin is a main part of red blood cells. It carries oxygen. If something is wrong with your red blood cells, if you don’t have enough of them, or if your hemoglobin is low, your cells won’t get enough oxygen. Symptoms of anemia -- like fatigue or pain -- happen because your organs aren't getting what they need to work the way they should.

Anemia is the most common blood condition in the U.S. It affects almost 6% of the population. Women, young children, and people with long-term diseases are more likely to have anemia. Important things to remember are:

  • Certain forms of anemia are passed down through your genes, and infants may have it from birth.
  • Women are at risk of iron-deficiency anemia because of blood loss from their periods and higher blood supply demands during pregnancy.
  • Older adults have a greater risk of anemia because of other medical conditions or because they don’t eat as well as they should.

There are many types of anemia. All have different causes and treatments. Some forms -- like the mild anemia that happens during pregnancy -- aren’t a major concern. But some types of anemia may create lifelong health problems.

Anemia Symptoms

The signs of anemia can be so mild at first that you might not even notice them. But if your condition gets worse, so do they. Symptoms generally include:

  • Dizziness
  • Fast or unusual heartbeat
  • Headache
  • Pain, including in your bones, chest, belly, and joints
  • Problems with growth, for children and teens
  • Shortness of breath
  • Skin that’s pale or yellow
  • Swollen or cold hands and feet
  • Tiredness or weakness
  • Vision problems

Anemia Types and Causes

There are more than 400 types of anemia, and they’re divided into three groups:

  • Anemia caused by blood loss
  • Anemia caused by decreased or faulty red blood cell production
  • Anemia caused by destruction of red blood cells

Anemia Caused by Blood Loss

You can lose red blood cells through bleeding. This can happen slowly over a long period of time, and you might not notice. Causes can include:

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Anemia Caused by Decreased or Faulty Red Blood Cell Production

With this type of anemia, your body may not create enough blood cells, or they may not work the way they should. This can happen because there’s something wrong with your red blood cells or because you don’t have enough minerals and vitamins for your red blood cells to work well. Conditions associated with these causes of anemia include:

Bone marrow and stem cell problems may keep your body from producing enough red blood cells. Some of the stem cells in the marrow that’s in the center of your bones will develop into red blood cells. If there aren’t enough stem cells, if they don’t work right, or if they’re replaced by other cells such as cancer cells, you might get anemia. Anemia caused by bone marrow or stem cell problems includes:

  • Aplastic anemia happens when you don’t have enough stem cells or have none at all. You might get aplastic anemia because of your genes or because your bone marrow was injured by medications, radiation, chemotherapy, or infection. Sometimes, there’s no clear cause of aplastic anemia.
  • Lead poisoning. Lead is toxic to your bone marrow, causing you to have fewer red blood cells. Lead poisoning can happen when adults come into contact with lead at work, for example, or if children eat chips of lead paint. You can also get it if your food comes into contact with some types of pottery that aren’t glazed right.
  • Thalassemia happens when your red blood cells can't mature and grow properly. It’s passed down in your genes and usually affects people of Mediterranean, African, Middle Eastern, and Southeast Asian descent. This condition can range from mild to life-threatening; the most severe form is called Cooley's anemia.

Iron-deficiency anemia happens because you don’t have enough of the mineral iron in your body. Your bone marrow needs iron to make hemoglobin, the part of the red blood cell that takes oxygen to your organs. Iron-deficiency anemia can be caused by:

  • A diet without enough iron, especially in infants, children, teens, vegans, and vegetarians
  • Certain drugs, foods, and caffeinated drinks
  • Digestive conditions such as Crohn's disease, or if you’ve had part of your stomach or small intestine removed
  • Donating blood often
  • Endurance training
  • Pregnancy and breastfeeding using up iron in your body
  • Your period

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Sickle cell anemia is a disorder that, in the U.S., affects mainly African Americans and Hispanic Americans. Your red blood cells, which are usually round, become crescent-shaped because of a problem in your genes. They break down quickly, so oxygen doesn’t get to your organs, causing anemia. The crescent-shaped red blood cells can also get stuck in tiny blood vessels and cause pain.

Vitamin-deficiency anemia can happen when you aren’t getting enough vitamin B12 and folate. You need these two vitamins to make red blood cells. This kind of anemia can be caused by:

  • Dietary deficiency: If you eat little or no meat, you might not get enough vitamin B12. If you overcook vegetables or don’t eat enough of them, you might not get enough folate.
  • Megaloblastic anemia: When you don’t get enough vitamin B12, folate, or both
  • Pernicious anemia: When your body doesn’t absorb enough vitamin B12

Other causes of vitamin deficiency include pregnancy, medications, alcohol abuse, and intestinal diseases such as tropical sprue and celiac disease.

Anemia associated with other conditions usually happens when your body doesn’t have enough hormones to make red blood cells. Conditions that cause this type of anemia include:

Anemia Caused by Destruction of Red Blood Cells

When red blood cells are fragile and can’t handle the stress of traveling through your body, they may burst, causing what’s called hemolytic anemia. You might have this condition at birth, or it could come later. Sometimes, the causes of hemolytic anemia are unclear, but they can include:

  • An attack by your immune system, as with lupus. This can happen to anyone, even a baby still in the womb or a newborn. That’s called hemolytic disease of the newborn.
  • Conditions that can be passed down through your genes, such as sickle cell anemia, thalassemia, and thrombotic thrombocytopenic purpura (TTP)
  • Enlarged spleen. This can, in rare cases, trap red blood cells and destroy them too early.
  • Something that puts strain on your body, such as infections, drugs, snake or spider venom, or certain foods
  • Toxins from advanced liver or kidney disease
  • Vascular grafts, prosthetic heart valves, tumors, severe burns, being around certain chemicals, severe hypertension, and clotting disorders

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Anemia Diagnosis

Your doctor will ask about your family history and your medical history. They’ll probably do some tests, including:

  • Blood smear or differential to count your white blood cells, check the shape of your red blood cells, and look for unusual cells
  • Complete blood count (CBC) to measure your red blood cells, hemoglobin, and other parts of your blood
  • Reticulocyte count to check for immature red blood cells

Anemia Treatment

Your treatment will depend on your type of anemia.

  • If you have aplastic anemia, you might need medication, blood transfusions (in which you get blood from another person), or a bone marrow transplant (in which you get a donor’s stem cells).
  • If you have hemolytic anemia, you might need medication that will hold back your immune system. You might have to see a doctor who specializes in heart or vascular problems.
  • If you have iron-deficiency anemia, you’ll probably need to take iron supplements and change your diet. If it’s caused by blood loss, you might have surgery to find and fix the bleeding.
  • Sickle cell anemia treatment may include painkillers, folic acid supplements, and antibiotics. You might also need a blood transfusion. A drug called hydroxyurea (Droxia, Hydrea, Siklos) can help your red blood cells keep their proper shape.
  • If you have vitamin-deficiency anemia, you’ll need to take supplements or change your diet to include more of certain nutrients.
  • Thalassemia doesn’t usually need treatment, but if your case is severe, you might have blood transfusions, a bone marrow transplant, or surgery.

WebMD Medical Reference Reviewed by Minesh Khatri, MD on October 12, 2019

Sources

SOURCES:

American Academy of Family Physicians.

The American Medical Athletic Association.

Albemarle Pulmonary Medical Associates, PA.

Gary W. Tamkin, MD, attending physician, Highland General Hospital -- Alameda County Medical Center, Oakland.

Cornell University Department of Animal Science.

PLoS One: "The Prevalence of Anemia and Moderate-Severe Anemia in the US Population (NHANES 2003-2012)."

CDC.

American Society of Hematology: “Anemia.”

Mayo Clinic: “Anemia,” “Sickle Cell Anemia.”

American Association for Clinical Chemistry: “Anemia.”

St. Jude Children’s Research Hospital: “Hydroxyurea Treatment for Sickle Cell Disease.”

Lupus Foundation of America: “What you need to know about anemia.”

National Heart, Lung, and Blood Institute: “Thrombotic Thrombocytopenic Purpura.”

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