Anemia, by definition, is a low iron-carrying capacity of blood. It is a condition where you do not have enough healthy red blood cells and hemoglobin in the blood. Hemoglobin is a protein found in the red blood cells that carries oxygen from the lungs to different tissues and organs of the body.

According to the World Health Organization, anemia is defined as a hemoglobin (Hb) concentration below 13 g/dl in men over 15 years of age, below 12 g/dl in non-pregnant women over 15 years of age, and below 11 g/dl in pregnant women.

Not having enough hemoglobin as in anemia, therefore interferes with this process and the supply of oxygen to different organs and tissues of the body suffers.

More than 25% of the world’s population is anemic, with about half of these suffering from iron deficiency. It is typically more common in women and children.

Anemia can cause various symptoms in the patient such as fatigue, weakness, and shortness of breath.


People with mild anemia may experience few or no symptoms. And, in people where symptoms occur, they can vary. The most frequent symptom of anemia is fatigue. Other symptoms and signs include:

  • Pale or yellowish skin complexion
  • Rapid or irregular heartbeat
  • Shortness of breath
  • Pain in chest
  • Headache
  • Dizziness

Types of anemia, their causes and symptoms

There are different types of anemia, and each type has typical symptoms. Some common types include:

  1. Iron deficiency anemia
  2. Vitamin B12 deficiency anemia
  3. Aplastic anemia
  4. Hemolytic anemia

1. Iron deficiency anemia

Iron deficiency anemia is the most common form of anemia. In this type of anemia, red blood cell production in the body suffers due to a lack of iron in the body.

Iron deficiency can develop due to several reasons:

  • A diet low in iron-containing foods
  • Menorrhagia (heavy bleeding during periods)
  • Too frequent blood donation
  • Certain digestive conditions, such as Crohn’s disease and malabsorption syndrome
  • Certain medications such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) can cause internal gastrointestinal bleeding. Even, medicines used to treat GERD can prevent your body from absorbing enough iron.

Symptoms of iron deficiency include fatigue, dizziness, and cold extremities

2. Vitamin B12 deficiency anemia

Vitamin B12 is essential for the production of RBCs. If a person does not consume or absorb enough B12, their RBC count may be low.

Causes of vitamin B12 deficiency anemia include

  • A diet having consistently low vitamin B12,
  • Pernicious anemia,
  • Gastric surgeries, and
  • Intestinal diseases like Crohn’s disease and celiac disease.

Some of its symptoms include:

  • Fatigue
  • Dizziness
  • Shortness of breath
  • Confusion and tendency to forget
  • Muscle weakness
  • Numbness or tingling in the hands and feet
  • Vision disturbances
  • Glossitis

3. Aplastic anemia

Aplastic anemia is a rare blood condition, which develops when the bone marrow cannot produce enough new red blood cells resulting in pancytopenia. It is mostly caused when an autoimmune disease damages the stem cells in the bone marrow. Despite this, the iron levels in the blood can be normal.

Besides an autoimmune cause, other causes of aplastic anemia can include:

  •  Radiation and chemotherapy treatments, which kill cancer cells along with stem cells in bone marrow
  • Exposure to toxic chemicals
  • Use of certain medications
  • Autoimmune disorders
  • Viral infections
  • Pregnancy

Symptoms of Aplastic anemia include:

  • weakness
  • increased frequency of infections
  • skin rashes

4. Hemolytic anemia

In this type of anemia, RBCs are destroyed faster than the body can produce new ones. Hemolytic anemia can be inherited from your parent or it can be acquired later in life.

Conditions that cause hemolytic anemia include:

  • autoimmune disease
  • infections such as hepatitis and typhoid
  • medications, such as penicillin, antimalaria medications, sulfa medications, or acetaminophen
  • bone marrow problems
  • inherited conditions such as sickle cell disease and thalassemia.

Hemolytic anemia symptoms include:

  • fever
  • dizziness
  • fatigue
  • jaundice
  • dark colored urine
  • pain in abdomen

Causes of anemia

Red blood cells are necessary for the body to survive. They contain hemoglobin, a complex protein that transports iron molecules. Hemoglobin carries oxygen from the lungs to the rest of the body.

Various health conditions can cause anemia and low RBC levels. There is no single cause and in some cases, it can be difficult to identify the cause.

However, there are three main causes of anemia. They include:

  • Loss of blood. Loss of blood is a common cause of iron deficiency anemia, which can lead to low levels of iron in the blood. When there is blood loss and a reduction in blood volume, the body draws water from neighboring tissues into the bloodstream to maintain blood volume. This dilutes the blood, which leads to a reduction in the RBC count. Blood loss can be in the acute form or it can be chronic (recurring). Acute blood loss is often due to surgery, childbirth, and trauma. Chronic blood loss, which is more common, can be caused by conditions such as peptic ulcers, hemorrhoids, menorrhagia, endometriosis, or cancer.
  • Decreased or impaired RBCs. The bone marrow produces stem cells, which develop into RBCs, white blood cells, and platelets. Diseases that can affect the bone marrow, disrupt the production of RBCs, and cause anemia. such diseases include:
      • Leukemia is a type of cancer in which there is excessive production of abnormal white blood cells and impaired production of RBCs.
      • Aplastic anemia is another bone marrow condition when few or no stem cells are present in the marrow.
      • Thalassemia is a hereditary type of anemia, in which the RBCs do not grow and mature as usual
  • Destruction of RBCs. RBCs have a life span of 120 days. Autoimmune hemolytic anemia is an autoimmune condition in which the immune system mistakes the RBCs for a foreign agent and attacks and destroys them before their natural life cycle.


If anemia is left untreated, it can cause several health problems, some of which can be serious. They include:

  • Severe fatigue. Severe anemia can make it impossible for you to do everyday household tasks.
  • Weakened immune system. Iron deficiency anemia can cause your immune system to become weak, making you more susceptible to frequent infections and a weakened body to fight them.
  • Restless legs syndrome. Iron deficiency anemia is a well-known cause of secondary restless legs syndrome.
  • Pregnancy complications. Pregnant women with folate deficiency anemia can cause pregnancy complications such as premature birth. Untreated iron deficiency anemia in pregnancy has significant adverse effects on the fetus and the pregnant woman.
  • Impaired development in childhood. Severe iron deficiency anemia in infancy and childhood can cause mental, cognitive, and motor developmental delays.
  • Heart complications. Anemia can lead to tachycardia, which is a rapid or irregular heartbeat. Due to very little oxygen in the blood, the heart has to pump faster and harder to ensure enough oxygen supply to all parts and organs of the body. Over time, this can lead to enlargement of the heart and subsequently even heart failure.
  • Death. If left untreated, anemia can cause multi-organ failure. Inherited anemias like sickle cell anemia (SCD) have a high rate of sudden death at an early age. According to a 1994 study, the average age of death in patients with SCD has been reported to be 42 years in males and 48 years in females.


To diagnose anemia, your healthcare provider will ask you about your medical and family history, do a physical exam, and order blood tests. Tests might include:

Complete blood count

Complete blood count is the most common and typically the first blood test to diagnose anemia. It measures

  • Hemoglobin levels. Typical adult hemoglobin levels are 14 to 18 gm/dL (grams per deciliter) for men and 12 to 16 gm/dL for women.
  • Hematocrit levels help to compare the volume of RBCs to the total blood volume. Typical adult hematocrit values are generally between 40% and 52% for men and 35% and 47% for women.
  • Red blood cell count helps to know if the number of RBCs in the blood is normal, low, or high in number. For adults, the normal range is generally 4.35 to 5.65 million red blood cells per microliter (mcL) of blood for men and 3.92 to 5.13 million red blood cells per mcL of blood for women.
  • Mean corpuscular volume (MCV) measures the average size of your red blood cells and gives a clue as to the cause of your anemia. For example, in iron-deficiency anemia, red blood cells are smaller than normal.

If RBC count, hemoglobin, and hematocrit levels fall below the normal range, a person is likely to be suffering from some form of anemia.

Other tests and procedures

If the CBC results show that you have anemia, you may need further tests, such as:

  • Hemoglobin electrophoresis measures the different types of hemoglobin in the blood and also looks for abnormal types of hemoglobin. Hemoglobin electrophoresis is recommended when microcytosis and hypochromia are detected in patients with risk factors.
  • A reticulocyte count test measures the number of young red blood cells in your blood, which helps to know if your bone marrow is making red blood cells fast enough.
  • The serum iron test measures how much iron is present in your blood.
  • The serum ferritin blood test is the most important test to measure the body’s ability to store iron and detect iron deficiency.
  • The total iron binding capacity (TIBC) test measures how much iron can be bound by the transferrin proteins in the blood for transportation through the body.
  • A transferrin test directly measures the level of transferrin in the blood. Transferrin is a blood plasma glycoprotein, which mediates the transport of iron (Fe) through blood plasma.

Some more tests

  • Your doctor may also order some more tests to rule out other causes of anemia such as kidney failure, lead poisoning (in children), and deficiencies of vitamins such as B12 and folic acid.
  • Your doctor may also order an endoscopy or colonoscopy to find the cause of bleeding in your GI tract if your stool test has revealed the presence of blood.
  • Your doctor may also order a bone marrow test to see if your bone marrow is functioning well and making enough blood cells.

Treatment of anemia

Your treatment will depend on your type of anemia.

Aplastic anemia treatment

Therapy for aplastic anemia depends on the cause, the severity, and your age. It may consist of only supportive care, immunosuppressive therapy, or hematopoietic stem cell transplantation (HCT). You might need immunosuppressants, blood transfusions, or a bone marrow transplant.

Treatment of hemolytic anemia

A doctor who specializes in vascular problems treats hemolytic anemia. Treatment may include medication such as corticosteroids or immunosuppressants to hold back your immune system and depress the rate of hemolysis.

Treating anemia caused by blood loss

If you have suddenly lost a lot of blood, you will be treated with intravenous fluids, oxygen, and possibly blood transfusion and iron.

If you suffer from chronic blood loss such as due to menorrhagia or hemorrhoids, the cause of bleeding is treated first to stop the bleeding and if the iron levels in blood are low, iron supplements are given along with advice to stick to an iron-rich balanced diet.

Sickle cell anemia treatment

Currently, a blood and bone marrow transplant is the only cure for sickle cell disease. However, everybody cannot go in for it because many such patients do not have a relative with a close enough genetic match to be a donor.

Sickle cell anemia treatment includes painkillers to manage pain episodes, folic acid supplements, intermittent antibiotics to prevent infections, and oxygen therapy only when oxygen levels drop below a critical threshold.

A drug called hydroxyurea is often prescribed for sickle cell patients. This medication helps keep blood cells in their proper shape, which helps them to move better and deliver oxygen to the body more easily

Crizanlizumab (Adakveo)is given by injection can keep blood cells from sticking together and occluding the blood vessels. It reduces the frequency of pain crises in adults

L-glutamine oral powder (Endari), recently approved by the FDA, reduces the frequency of pain crises and your trips to the hospital

You may need folic acid or vitamin B12 supplements if you have a deficiency of these vitamins.

Thalassemia treatment

If you have a mild thalassemia trait, you don’t need treatment. For moderate to severe thalassemia, you will need:

  • Frequent blood transfusions possibly every few weeks. In due course, this can cause a buildup of iron in your blood, which can damage body organs such as the heart and liver.
  • Chelation therapy to remove excess iron from your blood. This can be in the form of an oral medication, such as deferasirox (Exjade, Jadenu) or deferiprone (Ferriprox). Another drug, deferoxamine (Desferal), is given by an intravenous injection.
  • Stem cell transplant involves receiving infusions of stem cells from a well-matched donor, usually a brother or sister. This is the only treatment that can cure thalassemia and eliminate the need for lifelong blood transfusions and drugs to control iron overload.