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Pernicious anemia

  • Alternative Names

    Macrocytic achylic anemia; Congenital pernicious anemia; Juvenile pernicious anemia; Vitamin B12 deficiency (malabsorption)


    Monthly vitamin B12 injections are prescribed to correct the vitamin B12 deficiency. This therapy treats the anemia and may correct the neurological complications if taken early enough. In people with a severe deficiency, the injections are given more often at first.

    Some doctors recommend that elderly patients with gastric atrophy take vitamin B12 supplements by mouth in addition to monthly injections.

    There is also a preparation of vitamin B12 that may be given through the nose. For some people, taking vitamin B12 tablets by mouth in a very high dose can be an effective treatment.

    A well-balanced diet is essential to provide other elements for healthy blood cell development, such as folic acid, iron, and vitamin C.

    Support Groups

    Expectations (prognosis)

    The outcome is usually excellent with treatment.

    Any damage to nerves may be permanent, especially if treatment is not started within 6 months of when symptoms began.


    People with pernicious anemia may have gastric polyps, and they are at increased risk for gastric cancer and gastric carcinoid tumors.

    Brain and nervous system (neurological) problems may continue if treatment is delayed.

    Calling your health care provider

    Call your health care provider if you have symptoms of vitamin B12 deficiency.