Anemia happens when there is a decreased number of circulating red blood cells in the body. It is the most common blood disorder in the general population. Symptoms can include headaches, chest pains, and pale skin.
It currently affects more than 3 million Americans and an estimated 1.62 billion people, globally.
It often results when other diseases interfere with the body’s ability to produce healthy red blood cells or abnormally increase red blood cell breakdown or loss.
Fast facts on anemia
Here are some key points about anemia. More detail is in the main article.
Anemia affects an estimated 24.8 percent of the world’s population.
Pre-school children have the highest risk, with an estimated 47 percent developing anemia, globally.
More than 400 types of Anemia have been identified.
Anemia is not restricted to humans and can affect cats and dogs.
There are many potential causes of anemia.
The most common symptom of all types of anemia is a feeling of fatigue and a lack of energy.
Other common symptoms may include:
paleness of skin
fast or irregular heartbeat
shortness of breath
In mild cases, there may be few or no symptoms.
Some forms of anemia can have specific symptoms:
Aplastic anemia: fever, frequent infections, and skin rashes
Folic acid deficiency anemia: irritability, diarrhea, and a smooth tongue
Hemolytic anemia: jaundice, dark colored urine, fever, and abdominal pains
Sickle cell anemia: painful swelling of the feet and hands, fatigue, and jaundice
The body needs red blood cells to survive. They carry hemoglobin, a complex protein that contains iron molecules. These molecules carry oxygen from the lungs to the rest of the body.
Some diseases and conditions can result in a low level of red blood cells.
There are many types of anemia, and there is no single cause. It can sometimes be difficult to pinpoint the exact cause.
Below is a general overview of the common causes of the three main groups of anemia:
1) Anemia caused by blood loss
The most common type of anemia—iron deficiency anemia—often falls into this category. It is caused by a shortage of iron, most often through blood loss.
When the body loses blood, it reacts by pulling in water from tissues outside the bloodstream in an attempt to keep the blood vessels filled. This additional water dilutes the blood. As a result, the red blood cells are diluted.
Blood loss can be acute and rapid or chronic.
Rapid blood loss can include surgery, childbirth, trauma, or a ruptured blood vessel.
Chronic blood loss is more common in cases of anemia. It can result from a stomach ulcer, cancer, or tumor.
Causes of anemia due to blood loss include:
gastrointestinal conditions, such as ulcers, hemorrhoids, cancer, or gastritis
use of non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen
2) Anemia caused by decreased or faulty red blood cell production
Bone marrow is a soft, spongy tissue found in the center of bones. It is essential for the creation of red blood cells. Bone marrow produces stem cells, which develop into red blood cells, white blood cells, and platelets.
A number of diseases can affect bone marrow, including leukemia, where too many abnormal white blood cells are produced. This disrupts normal production of red blood cells.
Other anemias caused by decreased or faulty red blood cells include:
Sickle cell anemia: Red blood cells are misshapen and break down abnormally quickly. The crescent-shaped blood cells can also get stuck in smaller blood vessels, causing pain.
Iron-deficiency anemia: Too few red blood cells are produced because not enough iron is present in the body. This can be because of a poor diet, menstruation, frequent blood donation, endurance training, certain digestive conditions, such as Crohn’s disease, surgical removal of part of the gut, and some foods.
Bone marrow and stem cell problems: Aplastic anemia, for example, occurs when few or no stem cells are present. Thalassemia occurs when red blood cells cannot grow and mature properly.
Vitamin deficiency anemia: Vitamin B-12 and folate are both essential for the production of red blood cells. If either is deficient, red blood cell production will be too low. Examples include megaloblastic anemia and pernicious anemia.
3) Anemia caused by the destruction of red blood cells
Red blood cells typically have a life span of 120 days in the bloodstream, but they can be destroyed or removed beforehand.