Anemia

Anemia is a condition characterized by a low number of red blood cells or low hemoglobin levels—the iron-containing protein in red blood cells that carries oxygen. When these levels drop, cells throughout the body receive less oxygen than they need, causing symptoms such as fatigue, headache, shortness of breath, and pale skin and eyes.

Anemia is not a single disease but rather a symptom reflecting an underlying cause. Major causes fall into three categories: insufficient production of red blood cells, blood loss, and rapid destruction of red blood cells (hemolysis). The basic diagnostic test is a blood test measuring hemoglobin level and red blood cell count.

Types and causes

The most common form worldwide is anemia from iron deficiency, usually linked to inadequate dietary iron, heavy menstrual bleeding, pregnancy, or chronic blood loss from the digestive tract. Deficiency of vitamin B12 and folate causes anemia with enlarged cells. There are also hereditary forms such as sickle cell disease and thalassemia, and anemia associated with chronic diseases such as kidney failure or long-lasting infections. Parasites such as malaria and hookworm significantly increase anemia in many tropical regions.

Symptoms

Symptoms depend on how quickly the condition develops and how severe it is. When onset is gradual, the body can adapt and symptoms may be mild. Common symptoms include fatigue, difficulty concentrating, shortness of breath during physical activity, heart palpitations, and tingling in the hands and feet. In children, long-standing anemia can affect growth and learning.

Treatment and prevention

Treatment addresses the underlying cause. Iron deficiency is usually treated with iron supplements taken by mouth and dietary improvement. B12 deficiency requires supplementation, sometimes by injection. In severe cases, blood transfusion may be necessary. General prevention includes consuming food rich in iron and folate, treatment of parasites, and monitoring of pregnant women and young children, who are at higher risk.