Anemia occurs when your red blood cells do not carry enough oxygen to your body. The most common cause of anemia is not having enough iron. Treatment depends on the type of anemia you have.

Anemia Overview

Reviewed: May 8, 2014

Anemia is the most common blood disorder and it can occur in children and adults. Anemia is a condition in which your blood does not deliver enough oxygen to the rest of your body. This could happen if your blood has a lower than normal number of red blood cells or if your red blood cells do not contain enough hemoglobin. Hemoglobin is an iron-rich protein that gives blood its red color and helps red blood cells carry oxygen from the lungs to the rest of the body. If you have anemia, your body does not get enough oxygen-rich blood. As a result, you may feel tired or weak. You may also experience shortness of breath, dizziness, or headaches. Severe or long-lasting anemia can damage your heart, brain, and other organs in your body. Very severe anemia may even cause death.

There are several common types of anemia:

  • Iron-deficiency anemia occurs when you do not have enough iron in your body. Iron deficiency is usually due to blood loss but may occasionally be due to poor absorption of iron.
  • Vitamin-deficiency anemia results from low levels of vitamin B12 or folate (folic acid), usually due to poor dietary intake. Pernicious anemia is a condition in which vitamin B12 cannot be absorbed in the gastrointestinal tract.
  • Aplastic anemia is a rare form of anemia that occurs when the body stops making enough red blood cells. Causes of aplastic anemia include viral infections, exposure to toxic chemicals, drugs, and autoimmune diseases.
  • Hemolytic anemia occurs when red blood cells are broken up in the bloodstream or in the spleen. Hemolytic anemia may be caused by mechanical issues such as a leaky heart valve or an aneurysm, an infection, an autoimmune disorder, or congenital abnormalities in the red blood cell. Inherited abnormalities such as thalassemia and low levels of enzymes such as glucose-6 phosphate dehydrogenase deficiency also cause hemolytic anemia. Sickle cell anemia is a type of inherited hemolytic anemia in which the hemoglobin protein is abnormal, causing the red blood cells to be rigid and clog the circulation because they are unable to flow through small blood vessels.

Some diseases can affect the body's ability to make red blood cells. For example, some patients with kidney disease develop anemia because the kidneys are not making enough of the hormones that are needed to make new or more red blood cells. Also, Chemotherapy used to treat various cancers can impair the body's ability to make new red blood cells, and anemia often results from this treatment.

Anemia Symptoms

The most common symptom of anemia is feeling tired or weak. If you have anemia, you may find it hard to find the energy to do normal activities.

Signs and symptoms of anemia occur because your heart has to work harder to pump oxygen-rich blood through your body. Signs and symptoms of anemia include:

  • Weakness
  • Shortness of breath
  • Dizziness
  • Headache
  • Cold hands and feet
  • Pale or yellow skin
  • Chest pain
  • Fast or irregular heartbeat
  • Pounding or “whooshing” sound in your ears

Mild to moderate anemia may cause very mild symptoms or none at all.

Anemia Causes

The three main causes of anemia are blood loss, lack of red blood cells, and increased destruction of red blood cells.

  • Blood Loss. Blood loss is the most common cause of anemia, especially iron-deficiency anemia. Heavy menstrual periods or bleeding in the digestive or urinary tract can cause blood loss. Surgery, trauma, or cancer also can cause blood loss.
  • Lack of Red Blood Cell Production. Several conditions can prevent your body from making enough red blood cells: poor diet, abnormal hormone levels, some chronic diseases, and pregnancy.
    • Diet. A diet that lacks iron, folic acid (folate), or vitamin B12 can prevent your body from making enough red blood cells. Your body also needs small amounts of vitamin C, riboflavin, and copper to make red blood cells.
    • Hormones. Your body needs the hormone erythropoietin to stimulate the bone marrow to make red blood cells. A low level of this hormone can lead to anemia.
    • Diseases and Disease Treatments. Chronic diseases, like kidney disease and cancer, and their treatments, can make it hard for your body to make enough red blood cells.Pregnancy. Anemia can occur during pregnancy due to low levels of iron and folic acid and changes in the blood.
    • Aplastic Anemia. Some infants are born without the ability to make enough red blood cells. This condition is called aplastic anemia. Infants and children who have aplastic anemia often need blood transfusions to increase the number of red blood cells in their blood. Certain medicines, toxins, and infectious diseases, can also cause aplastic anemia.
  • High Rates of Red Blood Cell Destruction. Both acquired and inherited conditions and factors can cause your body to destroy too many red blood cells. One example of an acquired condition is an enlarged or diseased spleen, which is an organ that removes old red blood cells from the body. If the spleen is enlarged or diseased, it may remove more red blood cells than normal, causing anemia. Inherited conditions that can cause your body to destroy too many red blood cells include sickle cell anemia, thalassemias, and lack of certain enzymes. These conditions create defects in the red blood cells that cause them to die faster than healthy red blood cells. Hemolytic anemia is another condition in which your body destroys too many red blood cells. Inherited or acquired conditions or factors can cause hemolytic anemia. Such conditions include immune disorders, infections, certain medicines, or reactions to blood transfusions.

Many people are at risk for anemia because of poor diet, intestinal disorders, chronic diseases, infections, and other conditions. Women who are menstruating or pregnant and people with chronic medical conditions are most at risk for this disease. The risk of anemia increases as people grow older. People who engage in vigorous athletic activities may develop anemia as a result of red blood cells breaking down in the bloodstream.

If you have any of the following chronic conditions, you might be at greater risk for developing anemia:

  • Rheumatoid arthritis or other autoimmune disease
  • Kidney disease
  • Cancer
  • Liver disease
  • Thyroid disease
  • Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)

Anemia Diagnosis

Your doctor will diagnose anemia based on your medical and family histories, a physical exam, and results from tests and procedures. You may not experience symptoms related to anemia, or the symptoms you experience may be vague and difficult to identify, so anemia is sometimes hard to diagnose.

Your doctor may ask whether you have any of the common signs or symptoms of anemia or if you have had an illness or condition that could cause anemia.

Let your doctor know about any medicines you take, your diet, and whether you have family members who have anemia or a history of it.

Your doctor will do a physical exam to find out how severe your anemia is and to check for possible causes. During the exam, he or she will listen to your heart for a rapid or irregular heartbeat, listen to your lungs for rapid or uneven breathing, and feel your abdomen to check the size of your liver and spleen. Your doctor also may do a pelvic or rectal exam to check for common sources of blood loss.

You may have various blood tests and other tests or procedures to find out what type of anemia you have and how severe it is.

Anemia is diagnosed when a blood test shows a hemoglobin value of less than 13.5 gm/dl in a man or less than 12.0 gm/dl in a woman.

Living With Anemia

Many types of anemia cannot be prevented, but eating healthy foods can help you avoid both iron-and vitamin-deficiency anemia. Foods in your diet should have high levels of:

  • iron, which is found in beef, dark green leafy vegetables, dried fruits, and nuts
  • vitamin B-12, which is found in meat and dairy
  • folic acid, which is found in citrus juices, dark green leafy vegetables, legumes, and fortified cereals

A daily multivitamin will also help prevent nutritional anemias. Do not take iron supplements unless your health care provider tells you to.

Anemia Treatments

The treatment for anemia depends on what causes it.

Most causes of anemia can be treated. Treatment may increase your energy and activity levels, improve your quality of life, and help you live longer. With proper treatment, many types of anemia are mild and short term. However, anemia can be severe, long lasting, or even fatal when it is caused by an inherited or chronic disease or trauma.

Diet is an important treatment for anemia. If you are not getting enough vitamins, you may be advised to change your diet or take vitamins or iron or folic acid supplements.

A man-made version of the hormone erythropoietin (Epogen, Procrit) can be prescribed if your anemia is the result of cancer, kidney disease, or treatments for these diseases.

A blood transfusion may be necessary if your anemia is severe.