Pernicious anemia

Pernicious anaemia, also known as vitamin B₁₂ deficiency anaemia, is a disease in which there are not enough red blood cells due to a lack of vitamin B₁₂. The most common initial symptom is feeling tired. Other symptoms may include shortness of breath, pale skin, chest pain, numbness in the hands and feet, poor balance, a smooth red tongue, poor reflexes, and confusion. If treatment is not provided, some of these problems may become permanent.