Pernicious Anemia: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Pernicious Anemia?
A primary care doctor often starts the care of pernicious anemia. A hematologist, a doctor who treats blood diseases, can help with the low red blood cell count. A gastroenterologist, a doctor who treats stomach and gut problems, may also be involved. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is pernicious anemia?
Pernicious anemia is a drop in red blood cells that happens when the intestines cannot properly absorb vitamin B12. Anemia means the body does not have enough healthy red blood cells. Red blood cells carry oxygen to the body's tissues.
The body needs vitamin B12 to make red blood cells. Pernicious anemia is one type of vitamin B12 anemia.
Symptoms
Some people have no symptoms, and symptoms may be mild. When they do appear, they can include:
- Tiredness, low energy, or lightheadedness (feeling dizzy) when you stand up or exert yourself.
- Pale skin.
- Shortness of breath, mostly during exercise.
- Diarrhea or constipation.
- Nausea, vomiting, or loss of appetite.
- Heartburn.
- A swollen, red tongue or bleeding gums.
A low vitamin B12 level for a long time can damage nerves. Signs can include numbness and tingling in the hands and feet. Others are loss of balance and trouble concentrating. Some people also have confusion, short-term memory loss, depression, or irritability. Others have hallucinations. That means seeing or hearing things that are not there.
Causes and who gets it
The stomach makes a protein called intrinsic factor. This protein binds vitamin B12 so the intestines can absorb it. When the stomach does not make enough intrinsic factor, the intestines cannot properly absorb vitamin B12.
A common cause is a weakened, inflamed stomach lining, called atrophic gastritis. Another cause is an autoimmune condition. In this condition, the immune system attacks the intrinsic factor protein or the stomach cells that make it. Pernicious anemia can also occur after gastric bypass surgery. In rare cases, it is passed down through families.
In adults, symptoms are usually not seen until after age 30. The average age at diagnosis is 60. Slightly more women than men get it. You are more likely to get it if you are Scandinavian or Northern European. A family history also raises the risk. Certain diseases raise the risk too, including type 1 diabetes, Addison disease, Graves disease, vitiligo, and celiac disease.
How doctors diagnose it
Your health care provider will do a physical exam. Tests that may be done include a complete blood count (CBC), which counts your blood cells. Another is a vitamin B12 level. Doctors may also check for antibodies against intrinsic factor or the stomach cells that make it. They may also measure methylmalonic acid and homocysteine. These are two other substances in the blood.
Treatment
The goal of treatment is to raise your vitamin B12 level. Treatment often involves a shot of vitamin B12 once a month. People with very low levels may need more frequent shots at first. Some people may need shots regularly for the rest of their lives.
Some people can be treated with large doses of vitamin B12 supplements by mouth. A certain type of vitamin B12 may also be given as a spray into the nose.
Most people do well with treatment. It is important to start treatment early. Nerve damage can be permanent if treatment does not start within 6 months of symptoms. People with pernicious anemia may also have stomach polyps, which are small growths. They are more likely to develop stomach cancer. They are also more likely to break bones in the back, upper leg, and upper forearm.
When to see a doctor
Contact your provider if you have symptoms of vitamin B12 deficiency. Getting care early matters because nerve damage can be permanent if treatment is delayed.
Call 911 or go to the emergency room if you have chest pain or discomfort lasting two minutes or more, severe trouble breathing, fainting, or a sudden change in mental state.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either kind of doctor can do a first evaluation, follow your care over time, and help coordinate specialists.
Common questions
Is pernicious anemia the same as vitamin B12 deficiency?
No, pernicious anemia is one cause of vitamin B12 deficiency anemia. In pernicious anemia, the body destroys the stomach cells that make intrinsic factor. Other causes include some weight-loss surgeries and a strict vegetarian diet.
Can pernicious anemia be prevented?
No, there is no known way to prevent this type of vitamin B12 anemia. However, early detection and treatment can help reduce complications.
Can pernicious anemia cause permanent damage?
Yes, it can. Nerve damage can be permanent if treatment does not start within 6 months of symptoms. Brain and nervous system problems may also continue if treatment is delayed.
Will I need vitamin B12 shots for life?
Some people do. You may need shots regularly for the rest of your life. Some people are treated with large doses of vitamin B12 by mouth instead.
Sources
- MedlinePlus - Pernicious anemia
- National Organization for Rare Disorders - Anemia, Pernicious
- MedlinePlus - Vitamin B12 deficiency anemia
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
