Anemia
What is anemia?

Anemia is a clinical condition identified through blood tests. It is characterized by a hemoglobin level below the normal range for a person’s age, sex, and physiological state, such as pregnancy.

Hemoglobin is a protein in red blood cells, which are produced in the bone marrow. It binds oxygen and carries it to the body’s organs. When hemoglobin levels fall, tissues and organs receive less oxygen. This is why people with anemia often feel tired or weak or become short of breath during ordinary activities.

Anemia is one of the most common blood disorders worldwide and can affect people of any age. It is often a sign of another health problem, so identifying its cause matters.

📌 Statistical fact: According to the Global Burden of Disease Study 2019, an estimated 1.8 billion people worldwide had anemia in 2019.

Why does anemia occur, and what causes it?

Anemia develops through three main mechanisms: blood loss, insufficient red blood cell production, or the destruction of red blood cells faster than the bone marrow can replace them. Identifying the mechanism helps determine the cause and guide treatment.

Blood loss

Blood loss may be acute, meaning sudden, and can occur after an injury, surgery, or bleeding from the digestive tract. It may also be chronic, with smaller amounts of blood lost over a long period, as can happen with heavy menstrual periods or repeated bleeding from the digestive tract. Blood loss may be visible or hidden, meaning the bleeding cannot be seen.

Insufficient red blood cell production

To produce red blood cells, the body needs nutrients such as iron, vitamin B12, and folate, as well as a signal from the hormone erythropoietin. A deficiency can reduce production. In other cases, production is impaired by bone marrow disorders, cancerous blood cells infiltrating the marrow, chronic diseases, or certain medications.

Premature destruction of red blood cells (hemolysis)

Red blood cells normally live for about 120 days. In hemolysis, they are destroyed early, and the bone marrow may be unable to replace them quickly enough. The cause may be inherited, as in some forms of thalassemia, sickle cell disease, or G6PD deficiency. It may also be acquired, as in autoimmune hemolytic anemia, certain infections, or reactions to particular medications.

Who is at risk for anemia?

Anemia can affect anyone, but the risk is higher among people who lose blood, have greater nutritional needs, or consume or absorb too few essential nutrients. Chronic and blood disorders can also increase the risk. Groups at increased risk include:

People who lose more blood — Those with heavy menstrual periods or chronic blood loss, particularly from the digestive tract.
People with greater nutritional needs — Pregnant women, infants, children, and adolescents during periods of rapid growth.
People who consume or absorb fewer nutrients — Those with a poor diet or restrictive eating patterns, such as a vegan diet without an adequate source of vitamin B12, and people with conditions that impair nutrient absorption.
People with chronic diseases — Those with kidney disease, autoimmune or inflammatory conditions, chronic infections, or certain cancers.
Older adults — Several factors may occur together, including inadequate nutrient intake, poor absorption, and hidden blood loss.

What are the main types of anemia?

Anemia can be classified in several ways. By severity, it is described as mild, moderate, or severe. In general, a lower hemoglobin level may indicate more pronounced anemia, although symptoms also depend on how quickly it developed and the person’s overall health. By cause and mechanism, anemias can be grouped as follows.

Anemia caused by blood loss

This develops when the body loses red blood cells through bleeding and cannot replace them at the same rate. Blood loss may be acute, such as after an injury, surgery, or significant bleeding, or chronic, as with heavy menstrual periods or ongoing bleeding from the digestive tract. Chronic bleeding may be hidden.

Anemia caused by nutrient deficiency or insufficient production

Iron deficiency anemia — Occurs when the body does not have enough iron to produce hemoglobin. It can result from blood loss, inadequate iron intake, increased needs, or poor iron absorption. It is the most common form of anemia.
Sideroblastic anemia — The bone marrow cannot use iron properly to produce hemoglobin, so iron may accumulate in its cells.
Vitamin B12 or folate deficiency anemia — May result from inadequate intake, poor absorption, or certain diseases.
Aplastic anemia — The bone marrow does not produce enough blood cells, including red blood cells, white blood cells, and platelets.
Anemia of chronic disease — Certain diseases, especially those involving inflammation, affect red blood cell production. Chronic kidney disease can also cause anemia.
Anemia associated with blood cancers — Leukemia, lymphoma, and multiple myeloma can interfere with normal blood cell production in the bone marrow.
Chemotherapy-induced anemia — Chemotherapy drugs can temporarily reduce the bone marrow’s ability to produce new blood cells.

Anemia caused by premature red blood cell destruction

Acquired hemolytic anemia — May be caused by autoimmune diseases, infections, or certain medications.
Inherited anemias — Some inherited anemias involve hemolysis. They are linked to genetic changes affecting hemoglobin, the red blood cell membrane, or red blood cell enzymes. Examples include sickle cell disease, thalassemia, hereditary spherocytosis, and G6PD deficiency.

What are the symptoms of anemia?

Symptoms vary from person to person and depend on the severity of the anemia and how quickly it developed. When anemia develops gradually, the body may adapt, and a person may have no symptoms or may notice tiredness only during physical exertion. When it develops quickly, symptoms may be more pronounced. Other health conditions also play a role.

Common symptoms include:

Tiredness, physical weakness, lack of energy, or becoming tired quickly during everyday activities.
Dizziness, headaches, and difficulty concentrating.
Shortness of breath and a rapid heartbeat, especially during physical activity.
Feeling cold, particularly in the hands and feet.
Pale skin or mucous membranes; yellowing of the skin may also occur with some hemolytic anemias.

Mild anemia may cause no symptoms and be discovered during a routine blood test.

What are the warning signs?

Some signs require urgent assessment because they may indicate severe anemia, bleeding, or another serious problem. These include chest pain, marked difficulty breathing, fainting or loss of consciousness, and a very fast or irregular heartbeat. The following also require prompt assessment:

Signs of active bleeding — Vomiting blood, black tarry stools, major blood loss, or bleeding that does not stop.
Signs of another serious condition — Yellowing of the skin or dark urine, which may be linked to hemolysis; fever accompanied by unusual bruising or bleeding.

⚠️ Seek immediate medical attention if you have severe chest pain, marked difficulty breathing, fainting or loss of consciousness, a very rapid heartbeat, or signs of major bleeding.

How is anemia diagnosed?

Anemia is identified with a complete blood count (CBC). The hemoglobin level is the main measure used for diagnosis. The test also provides information about the red blood cell count, hematocrit, and red blood cell size. If their appearance needs to be assessed, the doctor may also request a microscopic examination of a peripheral blood smear. If the results show anemia, the doctor investigates its cause through the medical history, questions about anemia in the family, and additional tests as appropriate.

How is anemia treated?

Treatment depends on the cause of the anemia and is tailored by the doctor to the individual. It may include:

Iron, vitamin B12, or folate when the corresponding deficiency has been confirmed.
Treatment of the underlying condition, such as stopping bleeding or managing a chronic disease.
Medications that stimulate red blood cell production in certain cases, including some people with chronic kidney disease.
A blood transfusion in severe or urgent cases, based on medical assessment.
Other treatments specific to the type of anemia.

What complications can occur?

Untreated anemia can significantly affect quality of life. Possible consequences include:

Persistent tiredness and a reduced ability to work or be physically active.
Increased strain on the heart, which in severe or prolonged cases may be associated with heart problems.
Complications during pregnancy for the mother and baby.
Problems with growth and development in children, particularly when anemia is severe or prolonged.

If anemia is a sign of a serious disease, failing to investigate it may also delay that disease’s diagnosis.

Can anemia be prevented?

Some types of anemia can be prevented or their risk reduced, while others cannot. Preventive measures depend on the cause and a person’s individual risk:

Eat a healthy, varied diet that includes sources of iron, folate, and vitamin B12.
Take iron, vitamin B12, or folate when recommended by a doctor, particularly if your needs are increased or you are at risk of deficiency.
Identify and treat the cause of blood loss, such as heavy menstrual periods or bleeding from the digestive tract.
Attend checkups as advised by your doctor if you are in a higher-risk group, such as during pregnancy, after bariatric surgery, or if you have a chronic disease.

Inherited anemias and some forms associated with other diseases cannot be prevented simply through diet or supplements. Appropriate diagnosis, follow-up, and treatment are important in these cases.

When should you consult a doctor?

Consult a doctor if:

Symptoms such as tiredness, paleness, dizziness, headaches, a rapid heartbeat, or shortness of breath persist, worsen, or return.
You have very heavy menstrual periods, repeated bleeding, or unexplained changes in your stools.
You are at increased risk of anemia because of pregnancy, a restrictive diet, chronic disease, bariatric surgery, or a family history of inherited anemia.
Blood tests show low hemoglobin or other changes in the CBC, even if you have no noticeable symptoms.

Frequently asked questions

Can anemia be completely cured?
Anemia caused by iron, vitamin B12, or folate deficiency can often be corrected when the cause of the deficiency is also treated. Some people may need ongoing treatment. Not every type of anemia can be completely cured, but many can be treated and kept under control.

How long does anemia treatment take?
Blood test results may begin to improve within a few weeks, but treatment may continue for several months to replenish the body’s stores. The duration depends on the type and cause of the anemia.

Can anemia be managed with diet alone?
A suitable diet can help, especially when a deficiency is related to inadequate iron or vitamin intake. However, supplements or treatment of the underlying cause are often needed. The decision follows medical assessment and testing.

Why does evaluating anemia matter?

In many cases, anemia can be treated successfully once its cause has been identified. Because it is often a sign of another health problem, medical evaluation helps relieve symptoms and identify and treat the underlying cause.

Diagnosis through a blood test and regular medical follow-up help manage anemia and prevent complications. With appropriate treatment, many patients improve substantially.

📅 Book a consultation with a hematologist

🩺 Learn about our checkup programs

📌 Reviewed by Dr. Irma Lapaj, Hematologist, Klinika Kajo.

Anemia