What is microcytic anemia?

Microcytic anemia is a condition in which red blood cells are too small. Because red blood cells carry oxygen throughout the body, this condition can lead to fatigue and low energy. It can develop due to low iron levels or other medical problems.

While microcytic anemia can be diagnosed with a blood test, determining the cause may require additional diagnostic tests, such as imaging studies or colonoscopy (a tube with a camera to view the large intestine and rectum) or invasive procedures such as endoscopy Sexual testing (a tube with a camera to look at the digestive tract or other parts of the body).

Treatment may involve iron supplementation or management of the underlying medical cause. This article describes what microcytic anemia feels like and what you can do if you have it.

Types of

There are several types of microcytic anemia. Each of these conditions makes it difficult for the body to produce healthy red blood cells.

The most common types of microcytic anemia are:

  • Iron deficiency: You can get this mineral by eating meat, fish, beans, green leafy vegetables, and chicken. You may become deficient if you don’t eat enough iron-rich foods, or if you have trouble absorbing iron in your gastrointestinal system (digestive tract, from your mouth to your anus). Blood loss can also cause the body to lose iron and have low levels of iron.
  • Chronic diseases: Many diseases make it difficult for the body to produce red blood cells. This can lead to microcytic or normocytic (normal-sized red blood cells) anemia.
  • Lead Toxicity: When people are exposed to lead in the environment, lead poisoning usually occurs from water pollution or lead paint. This tends to have a more severe impact on children.
  • Thalassemia: This inherited disorder is a genetic defect that affects the formation of hemoglobin, a component of red blood cells.
  • Sideroblastic Anemia: This condition is characterized by sideroblasts in the bone marrow, which are premature red blood cells. Sideroblastic anemia can be acquired, and there are also genetic forms. It occurs due to a malfunction in the way the body uses iron to make hemoglobin.
  • Vitamin B6 deficiency: This vitamin can be obtained by eating meat, fish, chicken, turkey and chickpeas and is required for red blood cell production. Vitamin B6 deficiency can occur due to a lack of vitamin B6 in the diet, problems with the absorption of the digestive system, or excessive alcohol intake.
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Sometimes these types overlap, or you can have multiple types. For example, lead toxicity may cause sideroblastic anemia.

Symptoms of Microcytic Anemia

Symptoms of microcytic anemia develop over time. They are often vague and not specific to anemia.

Symptoms may include:

  • Fatigue, low energy, lethargy and sluggishness
  • general weakness
  • pale complexion
  • Dizziness
  • headache
  • irritability
  • difficulty concentrating
  • an enlarged spleen, which may make the abdomen appear larger

You can have all or some of these symptoms, with varying degrees of severity. More severe anemia tends to lead to more severe symptoms.


Other factors may affect the severity of symptoms of microcytic anemia, such as underlying medical conditions.

What causes microcytic anemia?

Microcytic anemia occurs when the body cannot produce normal-sized red blood cells. This can happen if you lack certain components of your red blood cells, or because of a disease that prevents your red blood cells from developing normally.

Conditions that commonly cause microcytic anemia include:

  • Not getting enough iron or vitamin B6 in the diet
  • inability to absorb enough iron or vitamin B6
  • chronic bleeding, for example due to gastrointestinal disease
  • acute bleeding, such as due to trauma
  • hereditary blood disease
  • Chronic health conditions (such as cancer) that prevent the normal development of red blood cells
  • Some medications that can cause microcytic anemia as a side effect

How does microcytic anemia develop

Red blood cells usually last about 120 days, and your body keeps making new red blood cells. Hemoglobin is an iron-containing protein that is an important component of red blood cells.

Oxygen entering the lungs binds to hemoglobin in red blood cells. It is transported through blood vessels throughout the body to maintain organ and tissue function.

When iron or hemoglobin levels are low, red blood cells don’t develop the way they should and don’t carry oxygen efficiently. Hemoglobin is red, and the small red blood cells may also be pale (pale) in color.

Iron deficiency is one of the factors that contribute to this problem. Acute bleeding can also lead to iron loss—it may take weeks for your diet or supplements to restore the lost iron. Chronic bleeding makes it difficult for the body to replenish its iron supply, which can lead to persistent microcytic anemia.

Thalassemia causes defects in the production of hemoglobin. Lead toxicity causes hemolysis (destruction of red blood cells).

Chronic diseases can cause hemolysis and may also interfere with erythropoiesis and iron metabolism. Sideroblastic anemia interferes with the way the body uses iron to make red blood cells.

How to Diagnose Microcytic Anemia

Microcytic anemia can cause signs found on physical exam, but not always. Microcytic anemia is diagnosed by a blood test. Sometimes, additional specific blood tests are used to determine the cause.

Myocytic anemia is sometimes detected during examinations and tests for other disorders or during routine physical examinations. Your healthcare provider may notice signs such as pale skin, a weak pulse, low blood pressure, increased heart rate, or an enlarged spleen (enlarged spleen).

Usually, a complete blood count (CBC) is part of a routine physical examination and is usually done if there are any signs or symptoms of anemia. Other blood tests you may need to further evaluate for microcytic anemia include blood smears, iron tests, genetic tests, or tests for lead levels. Sometimes additional diagnostic tests are needed.

Blood tests include:

  • CBC: For microcytic anemia, your red blood cell count may be normal or low, mean red blood cell volume (MCV) less than 80-100 femtoliters, red blood cell distribution width (RDW) normal or high, and mean red blood cell hemoglobin concentration (MCHC) Below 27–31 pg per cell.
  • Blood smear: In microcytic anemia, red blood cells appear small and usually pale when viewed under a microscope.
  • Genetic testing: Genetic testing can identify the genetic cause of thalassemia or sideroblastic anemia.
  • Iron levels: Iron levels in the blood can be measured to determine if a deficiency is present.
  • Lead levels: If you are concerned about lead toxicity, you can measure this toxic metal in a blood sample.

What is the red blood cell index?

Other diagnostic tests

Sometimes microcytic anemia is caused by bleeding or chronic disease. If you have this possibility, your doctor may order additional diagnostic tests to determine the cause of your anemia.

Tests you may need include:

  • Urinalysis: This is a test urine sample. It can identify blood in the urine, one of the signs of hemolysis or bleeding.
  • Imaging tests: If there is concern about the structural cause of cancer or bleeding, imaging tests such as ultrasound can help visualize it.
  • Colonoscopy: This invasive test can identify the source of intestinal bleeding.
  • Endoscopy: This invasive test can identify bleeding, cancer, or ulcers in the esophagus or stomach.
  • Bone marrow biopsy: A bone marrow biopsy may be required if there is concern about bone marrow disease or bone marrow cancer. Needles are used to remove bone marrow from bones for examination in the laboratory.

Your medical history, family history, symptoms, physical examination and blood work will be used to determine which diagnostic tests (if any) you may need.

What is the treatment for microcytic anemia?

There are many different treatments for microcytic anemia. Some treatments are used to help with symptoms, while others are used to help your body make normal red blood cells.

Blood transfusions may be needed to lessen the effects of severe anemia. This can resolve your anemia if it was caused by an acute event, such as blood loss from trauma or surgery. For chronic diseases, repeat blood transfusions may be required.

Other treatments focus on reducing the cause of anemia.

Examples of treatments include:

  • Surgery to repair bleeding wounds
  • iron substitute
  • Vitamin B6 Supplements
  • Treat underlying diseases, such as cancer
  • Treatment of lead poisoning
  • Manage thalassemia to avoid complications

Prognosis: what to expect

Microcytic anemia can improve with treatment. It may take weeks or months for you to feel better and your blood test results to improve. Depending on the cause, you may need to continue long-term treatment to prevent a recurrence of microcytic anemia.

For example, if you are unable to absorb iron from your diet, you may need to continue taking supplements to prevent the anemia from recurring. If you have thalassemia, you need a long-term treatment plan.


Microcytic anemia describes a condition in which red blood cells are very small. This can be caused by a variety of reasons, including nutritional deficiencies, genetic disorders, acute or chronic bleeding, or chronic illness. Microcytic anemia causes nonspecific symptoms. Diagnosis relies on blood tests.

Etiological evaluation is important because the cause guides treatment. Usually, treatment can normalize red blood cells and relieve symptoms, but sometimes long-term maintenance therapy is required.

VigorTip words

If you have microcytic anemia, it is important that you get a full diagnosis and get the treatment you need. Although medical attention is required, microcytic anemia is usually treatable, and having the condition does not limit your daily activities.

With treatment, you will gradually notice that you have more energy and less symptoms of anemia. Healthcare will also give you a better idea of ​​what symptoms to look for in the future.