Leukocytosis is a condition in which the number of leukocytes, that is, the white blood cells in the blood, is above normal, which in adults is up to 11, 000 per mm³.
Since the function of these cells is to fight infections and to assist in the workings of the immune system, their increase usually indicates that there is a problem that the body is trying to combat and so it can be a first sign of infection, for example.
Types of leukocytosis
Leukocytes are a group that includes several types of white blood cells and therefore the increase can occur in only one of these cell types. Thus, there are 5 main types of leukocytosis:
- Neutrophilia : is the increase of neutrophils, which usually happens due to excessive stress, exaggerated physical exercise, diabetes or some infections;
- Lymphocytosis : consists in the increase of the number of lymphocytes and is one of the most common types, appearing in cases of recurrent infections like influenza or allergy, for example;
- Monocytosis : is the increase in the number of monocytes and is a rarer change, which may indicate chronic infections such as tuberculosis, colitis or even leukemia;
- Eosinophilia : is an increase in the number of eosinophils and is usually more common in the case of allergies or infections by parasites or fungi;
- Basophilia : this is an increase in basophils and is a very rare change that can indicate problems such as asthma, sinusitis, anemia, colitis or even leukemia.
To assess the amount of these components in the blood, the doctor usually asks for a leukogram, which is included in the blood count. Normal values of leukocytes in the blood vary according to the person's age. See more about leukogram and what the normal reference values for each age.
Main causes of leukocytosis
Although the number of leukocytes can be altered by any problem that affects the body and there are more specific causes depending on the type of leukocyte that is altered, the most common causes of leukocytosis include:
1. Infections
Infections of the body caused by viruses, fungi or bacteria almost always cause changes in some of the major types of leukocytes and are therefore a major cause of leukocytosis.
Since there are many types of infections, the doctor needs to evaluate the symptoms that exist and ask for more specific tests to try to identify the specific cause and then be able to adjust the treatment. When the cause is difficult to identify, some doctors may choose to start treatment with an antibiotic because most infections are caused by bacteria, and evaluate if there is improvement in symptoms or if leukocyte values are regulated.
2. Allergies
Allergies such as asthma, sinusitis, or rhinitis are other common causes of increased numbers of leukocytes, especially eosinophils and basophils.
In these cases, the doctor usually asks for an allergy test to try to understand the reason for the allergy, especially if there are no symptoms that may help with the diagnosis. See how the allergy test is done.
3. Use of medicines
Some medications, such as Lithium or Heparin, are known to cause changes in blood cells, especially in the number of leukocytes, resulting in leukocytosis. For this reason, whenever there is a change in the blood test, it is very important to inform the doctor about the type of medication that is used frequently.
If necessary, your doctor may adjust the dose of the medicine you are taking or change it to another medicine that has a similar effect but does not cause so much change in your blood.
4. Chronic inflammation
Chronic or autoimmune diseases such as colitis, rheumatoid arthritis or irritable bowel syndrome can cause a constant inflammation process that causes the body to produce more leukocytes to counteract what is altered in the body. Thus, people with any of these conditions may have leukocytosis, even if they are being treated for the disease.
See the main symptoms of common chronic diseases like rheumatoid arthritis or the irritable bowel.
5. Cancer
Although it is more rare, the increase in the number of leukocytes may also indicate the development of a cancer. The most common type of cancer that causes leukocytosis is leukemia; however, other cancers such as lung cancer can also cause changes in leukocytes.
Whenever there is suspicion of cancer, the doctor may ask for other tests to try to confirm the presence. See the 8 exams that can help identify the presence of cancer.
What can cause leukocytosis in pregnancy
Leukocytosis is a relatively normal change in pregnancy, and the number of leukocytes may increase throughout pregnancy up to 14, 000 per mm3.
In addition, leukocytes also tend to increase after delivery due to stress caused in the body. Thus, the woman who was pregnant may have leukocytosis even after pregnancy for a few weeks.
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