The 12 Most Common Blood Diseases

There are many blood diseases, but very few are common in general society. Here we show you the variants of anemia, hemophilia, leukemia and some sporadic hematological symptoms.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 25 June, 2023

Blood is a liquid connective tissue that is responsible for distributing substances throughout the body and allowing homeostasis (internal balance). About 4-5 liters of blood (7% of the total weight) flow incessantly through the veins, arteries and capillaries, collecting oxygen from the lungs, carrying waste to the kidneys and many other functions. Unfortunately, there are certain common blood diseases that prevent this process.

These conditions are also known as hematological disorders, and they can occur due to poor hemoglobin synthesis, a lack of red blood cells, a reduced number of plasma cells, clotting difficulties, and many other reasons. Meet with us the 12 most interesting and common pathologies in this area.

What are the most common blood diseases?

When talking about hematological disorders, it’s necessary to have some prior knowledge, even if it’s basic knowledge. In the following list, we’ll explain the categories the different blood diseases are included in, according to their etiology and consequences.

• Hemoglobinopathies: These affect the production of hemoglobin, the protein responsible for binding oxygen and transporting it to all the body’s tissues. Genetic mutations in the genes that code for hemoglobin chains and thalassemias are found in this group.
• Anemias: These correspond to conditions in which there’s a low red blood cell count or low hemoglobin in the blood. As we’ll see in a minute, there are many types of anemia.
• Proliferative disorders: In these types of conditions, the bone marrow produces an excess of dysfunctional plasma cells, whether they’re red blood cells, white blood cells, or platelets. Blood cancers or leukemias are included in this category.
• Coagulopathies: A group of disorders in which the ability to form blood clots is disrupted. Thromboses are in this group.

As you can see, there are several categories the most common blood diseases are included in. Here are 10 of the most consequential, with special emphasis on their epidemiological situation and main symptoms. Keep reading.

1. Anemia

The term “anemia” refers to the decreased amount of red blood cells or hemoglobin in the blood. The World Health Organization (WHO) tells us that 1.62 billion people in the world are anemic, which translates into 24.8% of the total population. The global prevalence of this condition is summarized in the following points:

• 47.4% of preschool-age children show signs of anemia. As you can imagine, almost all cases are in low-income countries.
• 41.8% of pregnant women have anemia. However, it should be noted that it’s normal for the levels of red blood cells and hemoglobin to decrease a little during pregnancy due to the needs of the fetus.
• As for the geriatric population, 23.9% of the elderly are anemic.
• Non-pregnant women have an overall anemia rate of 30.2%. On the other hand, men are at a much lower figure, 12.7%.

As expected, women are generally more prone to anemia, as they actively lose iron during menstruation. In the following lines, we analyze different types of anemia and the symptoms that characterize them.

1.1 Anemia due to vitamin B12 deficiency

Folic acid and vitamin B12 are compounds necessary for the formation and maturation of red blood cells. Anemia caused by the deficiency of this micronutrient can be due to following a strict vegetarian diet without supplements, a poor diet in babies, and malnutrition during pregnancy.

1.2 Iron deficiency anemia

Without a doubt, iron deficiency anemia is the best known and most common in general society. However, its incidence in high-income regions is very low. This condition is caused by the lack of iron, which is essential in forming the heme group of hemoglobin.

Iron deficiency anemia can be caused by various clinical conditions. Among them, we highlight the following:

1. Loss of red blood cells (and therefore iron) faster than the body takes to synthesize new blood cells.
2. Iron malabsorption at the body level or lack of iron in the diet (less common in high-income countries).
3. Greater need for iron in the body, for example during pregnancy.
4. Internal or external bleeding: heavy menstrual periods, cancers, esophageal varices, peptic ulcers, and bleeding due to abuse of certain substances.

Iron deficiency anemia occurs with symptoms such as dizziness, weakness, headaches, palpitations, trouble concentrating, brittle nails, pale skin color, and shortness of breath in the most severe cases. Depending on the causative agent of iron loss, treatment will vary drastically, since supplements in the form of pills aren’t always enough.

1.3 Hemolytic anemia

On average, red blood cells circulate in the blood for 3 to 4 months (120 days) until they’re destroyed and recycled in the spleen. As indicated by the United States National Library of Medicine, in hemolytic anemia these cells break down much earlier than normal.

This phenomenon may be due to various pathological events, among which the following stand out:

• Autoimmune diseases: In these cases, the white blood cells and other defender cells interpret the red blood cells as a threat and destroy them before their time.
• Exposure to chemical and toxic agents and certain drugs.
• Certain infections and cancers.
• Blood transfusions with an incompatible sample.

Treatment will vary depending on the etiology, but, in the most severe cases, emergency blood transfusions are always required. In immune hemolytic anemia, corticosteroid drugs are usually used, as they’re immunosuppressive and reduce the attack on the red blood cells. Unfortunately, this pharmacological group favors the appearance of other infections.

1.4 Idiopathic aplastic anemia

In this type of anemia, the patient’s bone marrow doesn’t make enough red blood cells. This is one of the less common blood diseases on the list, because research has shown that it affects 1 to 9 patients per million inhabitants. In any case, it’s important to review it as another of the existing anemic variants.

In this condition, the trigger is clear damage to the bone marrow stem cells, responsible for synthesizing all the cell bodies that travel through the blood. The use of certain drugs, exposure to radiation, chemotherapy, and some immune disorders favor the appearance of this clinical picture.

2. Hemophilia

Simply by looking at anemic conditions, we have already described 4 of the most common blood diseases, but there are many more. Now we turn to hemophilia, an inherited bleeding disorder in which blood doesn’t clot properly. As indicated by the Centers for Disease Control and Prevention, this makes patients prone to bleeding.

Hemophilia can be divided into 3 types: A, B, and C. We tell you the peculiarities of each of these blood diseases in the following lines.

2.1 Hemophilia A

This is the most common type, affecting 1 in every 5,000 newborn males. In this clinical picture, the defect is found in the lack of synthesis of blood coagulation factor VIII. Without sufficient concentration of this compound in the plasma, the blood cannot clot properly and the patient bleeds excessively.

This condition is much more common in men than in women, since the genetic mutation that causes it is found on the X chromosome. Remember that men are XY and women XX, so a female with the mutation on an X chromosome will only be a carrier (since she has another functional X), while a male with a “defective” X will always be symptomatic.

2.2 Hemophilia B

This variant is much less common than the previous one, occurring in 1 in 30,000 male newborns. In this case, the clotting factor that isn’t synthesized properly is IX, but the gene that encodes it is also found on the X chromosome. For this reason, it’s once again an almost exclusive disease of the male gender.

2.3 Hemophilia C

More recently described, hemophilia C is caused by a lack of synthesis of clotting factor XI. It affects 1 in 100,000 people, so it’s considered much less common than variants A and B. In any case, it has an essential difference with them.

In this case, the gene mutation that causes the disease is found on chromosome 4. Therefore, it’s an autosomal condition (of the non-sex chromosomes) that affects men and women equally. It’s also characterized by the appearance of excessive bleeding and the inability to coagulate the wounds.

3. Leukemia

With anemia and hemophilia and their variants, we have cited 7 high-prevalence blood diseases, but we can’t leave this topic without mentioning the word cancer. Although it isn’t a solid tumor, leukemia is one of the most well-known and feared malignant neoplasms in general society.

The National Cancer Institute defines this condition as “cancer that begins in the tissues that make up the blood, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the bloodstream.” This can be acute (of rapid onset) or chronic (that progresses slowly).

Leukemia is the most common type of cancer in children and adolescents, accounting for 1 in 3 cancers in this age group. In addition, 300,000 new cases are diagnosed each year worldwide. Some of its general symptoms are the following:

• Fevers and chills
• Persistent fatigue, accompanied by general weakness
• Frequent and serious infections
• Unjustified weight loss
• Swollen lymph nodes and an enlarged spleen
• Recurrent bleeding and easy bruising
• Red spots on the skin
• Bone pain
• Hyperhidrosis (excessive sweating, especially at night)

As in the rest of the clinical pictures cited so far, leukemia can be divided into various variants according to its etiology. Let’s see in detail what each of them consists of.

3.1 Acute lymphocytic leukemia (ALL)

This is the most common type in infants and young people, and 3 out of 4 leukemias occur in this age group. In this cancer, the bone marrow produces an excess number of lymphoblasts, immature cells that take the place of healthy white blood cells. Chemotherapy is always the first treatment to go to, although stem cell transplants are sometimes required.

3.2 Acute myelogenous leukemia (AML)

Acute myelogenous leukemia is one of the most common types of leukemia among adults, especially in the male population. In this case, there’s an overgrowth of another type of immature white blood cell, called myeloblast. It’s of rapid onset and the survival rate in people older than 20 about 5 years after diagnosis is 26%.

3.3 Chronic lymphocytic leukemia (CLL)

This clinical picture differs from acute lymphocytic leukemia in that it develops chronically, that is, slowly but surely. As indicated by the American Cancer Society, it’s the most common type of blood cancer in the adult population, even above AML. In this case, patients may not experience symptoms until several years after the onset of the disease.

3.4 Chronic myelogenous leukemia (CML)

This type of leukemia is associated with a chromosomal abnormality, called the Philadelphia chromosome. It’s a rare variant, but it’s one of the few cancers that can be permanently cured with bone marrow transplantation. However, this option is only considered in patients in whom other options have failed, as it’s quite risky.

4. Immune thrombocytopenia

Immune thrombocytopenia is another common blood disease that has symptoms that are similar to hemophilia. It’s characterized by a marked difficulty in clotting, but, instead of lacking clotting factors, in this case the deficit is in the number of circulating platelets.

An annual incidence is estimated in adults of between 1/62,500 and 1/25,600 inhabitants, with a female/male ratio of 1.3: 1. Some of the most common symptoms are:

• A tendency to bruise
• Superficial skin bleeding that appears as unexplained red pits – these are known as petechiae
• Unexplained nose or gum bleeding, especially when brushing your teeth
• Bloody stools and urine
• Excessive and abundant menstrual periods in women

Again, corticosteroids are usually one of the first routes of action, although, in these cases, drugs that stimulate platelet production are also often prescribed. If the condition is very severe, platelet aggregate transfusions may be required.

The most common blood diseases: a summary

In this article, we have mentioned 12 common blood diseases, with special emphasis on the variants of anemia, hemophilia, and leukemia. This isn’t surprising, as these hematological disorders are the best known at a general level and the ones that are the cause for most visits to the doctor’s, especially if we talk about iron deficiency anemia in women.

Be that as it may, almost all blood diseases produce similar symptoms: paleness, easy bleeding, weakness, confusion, fatigue, and generalized weight loss. If you notice any of the aforementioned clinical symptoms, don’t hesitate to go and see a doctor as soon as possible.