Everything you should know about Microcytic anemia

Today we will discuss microcytic anemias which are the most common types of anemia.

Anemia is defined as the reduced oxygen-carrying capacity of the blood which is generally due to reduced hemoglobin or defective hemoglobin.

Anemia can be classified depending on causes or we can classify anemia depending on how the red blood cell appears microscopically.

What is microcytic anemia?

Microcytic anemia is defined as anemia in which the red blood cells are smaller than usual. Micro is small and cytes are cells. 

MCV is also known as the mean corpuscular volume is the measure of red blood cells’ average size. In microcytic anemia in which red blood cell size is reduced, the MCV is less. If MCV is less than 83 it is considered microcytic anemia.

Amongst all other types of anemia, microcytic anemia is the most common variety of anemia.

Microcytic anemia is further classified as:

  • Microcytic hypochromic anemia
  • Microcytic normochromic anemia
  • Microcytic hyperchromic anemia

Microcytic hypochromic anemia

Microcytic hypochromic anemia is a type of microcytic anemia. 

This form of anemia is characterized by smaller red blood cells and hypochromic. Hypo is less and hypochromic is less color or pigmentation.

This type of red cell morphology occurs when red cells are smaller and they also have less hemoglobin in them. 

Causes of microcytic hypochromic anemia:

  • Iron deficiency
  • Thalassemia
  • Sideroblastic anemia
  • Lead poisoning
  • Alcohol abuse
  • Chronic diarrhea
  • Vitamin C deficiency
  • Chronic blood loss like excess blood loss during menstruation
  • A parasitic infestation of gut

Microcytic normochromic anemia

Generally, the following conditions cause normocytic normochromic anemia but in some people, it may cause microcytic normochromic anemia.

In this form of anemia red blood cells are small in size but they are adequately pigmented compared to their size.

  • infectious diseases, such as tuberculosis, HIV/AIDS, or endocarditis
  • inflammatory diseases, such as rheumatoid arthritis, Crohn’s disease, or diabetes mellitus
  • kidney disease

Microcytic hyperchromic anemia

This is a rare form in which red blood cells are smaller in size but they are more pigmented than the normal.

This type of morphology of the red blood cells may be seen in hereditary spherocytosis.

What are the symptoms of microcytic anemias?

Symptoms of microcytic anemia are like any other form of anemia. These symptoms are caused by the decreased oxygen-carrying capacity of the blood. 

Some common symptoms include:

  • Fatigue
  • Feeling of weakness
  • Loss of appetite
  • Breathlessness
  • The increased pallor of the skin
  • Irritability
  • Increased heart rate
  • Pica: Eating non-edible items like soil and chalks
  • In children, inability to gain weight and height

Other common symptoms that may indicate the underlying cause of anemia include:

  • Blood in stools
  • Chronic diarrhea
  • History eating the pain of walls
  • History of staying in an industrial area where the lead is indiscriminately used.
  • Not eating fresh vegetables and fruits
  • Food faddism
  • Increased sleep and an increased feeling of cold
  • Symptoms of kidney disease
  • Cough, mild grade fever, and weight loss

Overall the symptoms are vague and nonspecific, further investigations are usually needed to fund out the cause of anemia.

What investigations are needed?

Following basic investigations are needed to find out the anemia and its cause. Knowing the cause is important as the treatment further depends upon the underlying cause of the anemia.

Blood investigations


This blood HBCBC investigation detects the hemoglobin level and other indicators like MCV, MCH, red blood cell count, white blood cell count, and platelet counts.

In iron deficiency anemia hemoglobin is low with increased platelet count and low red blood cell count. MCV is reduced with reduced MCH and MCHC.

In thalassemia, the picture can be similar to iron deficiency anemia.

Peripheral smear

In this blood test, the smear of blood examined with the help of a microscope, and the morphology of various cells is noted.

Any abnormal cells if found are noted and counted.

Reticulocyte count

This blood test helps to differentiate the hemolytic anemias in which reticulocyte count is usually higher.


If thalassemia or other hemoglobin defect is suspected cause of anemia HB electrophoresis is done to find out the cause of the anemia.


Liver function tests help to detect the increased bilirubin level which can be found in hemolytic anemia. Additionally, it helps to detect any liver disease which can be the cause of anemia.

Renal function tests help to rule of renal disease which can be the cause of anemia in some patients.


This blood test helps to detect any chronic cause of anemia like chronic infection or chronic inflammatory condition.

Other blood examinations like serum iron-binding capasity, serum ferritin level, total iron-binding capacity are used depending on how the basic blood level findings.

Stool examination

Stool examination helps to detect the cause of blood loss if any. It helps to detect the parasitic infection if it is suspected so.

What is the treatment for microcytic anemias?

The treatment of microcytic anemias depends on the underlying cause of the disease. 

The aim of the treatment is correcting the underlying cause if possible and normalizing the hemoglobin with that.

Severe acute anemia like anemia of blood loss may need emergency treatment with blood transfusion.

Iron deficiency anemia needs an iron supplement which can be provided orally or by injection. 

Other diseases like thalassemia need blood transfusion depending on the severity of the disease. For severe thalassemia, bone marrow transfusion is the only definitive treatment available for treatment.

Other diseases like chronic conditions and inflammatory conditions should be treated depending on the underlying cause. 

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