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Pernicious Anemia: Here's What You Need to Know

Pernicious Anemia: Here's What You Need to Know

Our body needs vitamin B12 to form healthy red blood cells. Pernicious anemia is a condition wherein the stomach does not have enough of the proteins called intrinsic factor. These are necessary to help the body absorb vitamin B12. As a result, the red blood cells don’t divide normally and become too large (megaloblastic anemia).

If left untreated, pernicious anemia can lead to problems in the cardiovascular system and nervous system. This disease may also increase the risk of developing fractures and gastric cancer.

Pernicious anemia can be diagnosed in infants and in adults. Adult type pernicious anemia is more common and is typically diagnosed in patients around 60 years old. This disease is also more common in women than in men. People who have multiple myeloma, a type of cancer, are likely to be diagnosed with pernicious anemia.

Causes of pernicious anemia

Autoimmune Disease

The immune system attacks the cells lining the stomach. These cells lining the stomach produce intrinsic factor, which is necessary for vitamin B12 absorption.


Surgically removing part of the stomach and the small intestine can significantly reduce the cells producing intrinsic factor.

Genetic Disorder causing pernicious anemia

In rare instances, children inherit a disease that impedes the stomach from producing intrinsic factor.

Bacteria in the small intestine

When there is too much bacteria in the small intestine, they may feed on the vitamin B12 before the body absorbs it. This is more common in elderly people.

Diseases that interfere with vitamin B12 absorption

People with HIV may develop pernicious anemia. Celiac disease can also damage the part of the small intestine where vitamin B12 is absorbed.


Some medicines, especially antibiotics and some diabetics medication, can cause a disturbance in the bacterial growth in the small intestines which can prevent proper absorption of vitamin B12.

Tapeworms in the stomach

When a tapeworm infects the stomach and the intestines, it feeds on the nutrients the body is trying to absorb. This may can cause nutrient deficiency, including vitamin B12 deficiency.

Diet leading to pernicious anemia

Strictly vegetarian and vegan diets, if not practiced properly, can cause a deficiency since vitamin B12 is mainly found in meat, eggs, and poultry.

Insufficient Vitamin B12 in pregnant mothers

When a pregnant woman is not getting enough vitamin B12 for her and her baby, this may lead to the infant not having enough time to store the vitamin in their body. These infants often develop anemia months after they are born.

Signs and symptoms of pernicious anemia

When a person is developing pernicious anemia, they manifest signs and symptoms that apply to any type of anemia. However, they also manifest symptoms that are specifically caused by the lack of vitamin B12 in the body.

Symptoms and signs include:

  • Fatigue
  • Dyspnea or shortness of breath
  • Chest Pain
  • Nausea
  • Irritability
  • Problems in balancing
  • Numbness and tingling in the hands and feet
  • Cold hands and feet
  • Digestive problems such as diarrhea and heartburn
  • Swollen or smooth and tender tongue
  • Bleeding gums
  • Yellowing of the skin (mild jaundice)
  • Neurological problems such as depression and memory loss

Diagnosis of pernicious anemia

A doctor will conduct a physical exam. They will also check for possible issues with the patient’s mental state.

Blood is extracted from the patient for a complete blood count (CBC). The CBC confirms if the patient has anemia. Further tests need to be conducted to confirm the type of anemia a person has.

Treatment of pernicious anemia

Treatment for pernicious anemia depends on what’s causing it. A doctor takes into consideration the age, a person’s overall health, ongoing treatments for other diseases, their tolerance for certain medications, and the severity of the anemia.

Treatment includes:

  • Vitamin B12 – Initially, the patient needs a daily dose of B12. Afterward, the doctor may make it weekly, then monthly. Most patients need B12 for life.
  • Change in diet – If the cause of the vitamin B12 deficiency is diet, aside from vitamin B12 supplements, the doctor might also ask the patient to add more food rich in vitamin B12.

Pernicious anemia may be caused by other conditions besides vitamin B12 deficiency. That condition must be treated for the patient’s symptoms to improve.

If the condition is caused by a medication, the doctor would have to prescribe an alternative medication or adjust the dose of the current medication.

Key takeaway

Pernicious anemia is a type of disease that is commonly caused by the body’s inability to absorb vitamin B12. Vitamin B12 is necessary for the production of healthy red blood cells. Pernicious anemia can be due to other diseases, a poor diet, or a genetic disorder. If left untreated, it can lead to complication in the heart and brain.

Learn more about Anemia here.


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Hello Health Group does not provide medical advice, diagnosis or treatment.


Pernicious Anemia, https://www.nhlbi.nih.gov/health-topics/pernicious-anemia

Accessed March 17, 2021


Anemia, Pernicious, https://rarediseases.org/rare-diseases/anemia-pernicious/

Accessed March 17, 2021


Pernicious anemia, https://www.mountsinai.org/health-library/diseases-conditions/pernicious-anemia

Accessed March 17, 2021


Vitamin B-12 Deficiency Anemia, https://www.cedars-sinai.org/health-library/diseases-and-conditions/a/anemia-of-b12-deficiency.html

Accessed March 17, 2021


Pernicious Anemia, https://www.rush.edu/conditions/pernicious-anemia

Accessed March 17, 2021


Megaloblastic Anemia | Diagnosis & Treatment, https://www.childrenshospital.org/conditions-and-treatments/conditions/m/megaloblastic-anemia/diagnosis-and-treatment

Accessed March 17, 2021

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Written by Fidelis Tan Updated Jun 22
Fact Checked by Hello Doctor Medical Panel