Key Points

• Pernicious anemia is a condition in which the body can't make enough healthy red blood cells because it doesn't have enough vitamin B12.
• People who have pernicious anemia can't absorb enough vitamin B12 due to a lack of intrinsic factor, a protein made in the stomach. This leads to vitamin B12 deficiency. In people who have pernicious anemia, the cells that make intrinsic factor are destroyed.
• Other conditions and factors also can cause vitamin B12 deficiency. Examples include infections, surgery, medicines, and diet. Technically, the term “pernicious anemia” refers to vitamin B12 deficiency due to a lack of intrinsic factor. Often, vitamin B12 deficiency due to other causes also is called pernicious anemia.
• Without enough red blood cells to carry oxygen to your body, you may feel tired and weak. Severe or long-lasting pernicious anemia can damage the heart, brain, and other organs in the body. The condition also can cause other complications, such as nerve damage, neurological problems (such as memory loss), and digestive tract problems.
• Pernicious anemia is more common in people of Northern European and African descent. In the United States, older people are at higher risk for the condition. Pernicious anemia also can occur in younger people and other population groups.
• The signs and symptoms of pernicious anemia are due to a lack of vitamin B12 (vitamin B12 deficiency). Without enough vitamin B12, your body can't make enough healthy red blood cells. This causes anemia.
• Some of the signs and symptoms of pernicious anemia, such as fatigue (tiredness), shortness of breath, and dizziness, apply to all types of anemia. Other signs and symptoms, such as muscle weakness, memory loss, and nausea (feeling sick to your stomach), are specific to a lack of vitamin B12.
• Your doctor will diagnose pernicious anemia based on your medical and family histories, a physical exam, and the results from tests. Your doctor will want to find out whether the condition is due to a lack of intrinsic factor or another cause.
• Doctors treat pernicious anemia by replacing the missing vitamin B12 in your body. This is done using vitamin B12 pills or shots. People who have pernicious anemia may need lifelong treatment. If your doctor can find the cause of your pernicious anemia, you may get treatment for that problem.
• You can't prevent pernicious anemia that's due to a lack of intrinsic factor. However, if you have pernicious anemia because of dietary factors, you can take steps to prevent it. Eating foods high in vitamin B12 can help prevent low vitamin B12 levels. Your doctor also may advise taking vitamin B12 supplements.
• With proper treatment, people who have pernicious anemia can recover, feel well, and live normal lives. See your doctor regularly for checkups and ongoing treatment. Take vitamin B12 supplements as your doctor advises. This may help prevent anemia symptoms and complications.
• If you have pernicious anemia, tell your family members. Pernicious anemia can run in families, so they may be more likely to develop the condition.