Pernicious anemia

Pernicious anaemia is an autoimmune condition of the stomach in which too little intrinsic factor is made, so the intestine cannot absorb vitamin B12 and healthy red blood cells fall short. It is more common in older adults, especially women, and in people with a family history. The immune system may attack intrinsic factor itself or the stomach cells that make it; other autoimmune conditions such as Addison disease and vitiligo raise the risk, as does gastric bypass surgery. Some people have no symptoms; others have fatigue, pale skin, breathlessness and a sore red tongue, and prolonged deficiency can damage nerves, causing numbness, tingling and confusion. Diagnosis uses blood tests, including a blood count, vitamin B12 level and antibodies against intrinsic factor or the cells producing it. Treatment replaces vitamin B12, usually by injection, and is often lifelong.

Seek urgent care for unusual bleeding or bruising, breathlessness at rest, or a swollen painful leg. See a doctor for persistent tiredness, pale skin, or any symptom of anaemia in a man or a woman after the menopause, which always needs a cause to be found. Call the local emergency number for any symptom that is sudden and severe. This page is a reference for healthcare professionals and does not replace an assessment.