If the number of white blood cells in the blood exceeds the normal value, doctors speak of leukocytosis, which in itself is not dangerous in moderation, but can be a harbinger of the presence of other, more serious diseases.

What is leukocytosis?

The only way to detect an elevated white blood cell count is with a blood test. This routine medical check-up examines the condition of the blood and its composition of the most important components, including the white blood cells. See AbbreviationFinder for abbreviations related to Leukocytosis.

The term leukocytosis is derived from the Greek foreign word syllable “leukos”, which translates as “white”. What is meant by leukocytosis is the white blood cells.

Human blood is made up of a variety of different components, one of which is the white blood cells. Since each of the blood components has been assigned its own task, it is important for the body that the concentration of the individual components is kept in the right amount.

This is no longer the case with leukocytosis, since the white blood cells are more common in the blood than they should be. Normally, the amount of white blood cells found in the body of a healthy person is around four to eleven microliters. If the limit of eleven liters is exceeded, leukocytosis is present. At extreme values ​​beyond 100,000 microliters, there is a case of so-called hyperleukocytosis.


The causes of leukocytosis can be different, ranging from harmless to harbingers of life-threatening diseases. As a rule, the leukocytosis is caused by a harmless infection. One of the main tasks of the white blood cells is the immune system.

If the immune system registers a pathogenic foreign body that has penetrated the body, it is up to the white blood cells as one of the supporting elements of the non-specific immune system to track down and destroy the foreign body. In this respect, it is not surprising if the number of white blood cells increases as part of an infection; a leukocytosis in this case is neither dangerous nor worthy of further investigation.

Especially those affected by chronic inflammatory diseases, such as patients with Crohn’s disease, a chronic intestinal inflammation, often have increased amounts of white blood cells in their blood. However, leukocytosis can also be caused by the administration of medication. It is known that anti-inflammatory agents such as glucocorticoids can unintentionally stimulate the body to produce more white blood cells.

Much more serious, however, and here the more detailed examination of the leukocytosis becomes mandatory, is the fact that excessive concentrations of white blood cells – like any other type of blood abnormality – can be a possible sign of leukemia, the blood cancer.

Diagnosis & History

Unlike diseases in the narrower sense, leukocytosis lacks its own characteristic symptoms. It is unobtrusive for the patient, precisely because it causes neither pain nor other symptoms.

The only way to detect an elevated white blood cell count is with a blood test. This routine medical check-up examines the condition of the blood and its composition of the most important components, including the white blood cells. If leukocytosis is detected, it depends on various factors whether further investigations need to be arranged.

If there is a slight increase in the number of white blood cells, the doctor treating you will use this as an opportunity to carry out another blood test at the next doctor’s visit to determine whether the slight leukocytosis was only of a temporary nature and whether the blood count has returned to normal.

The same applies if the doctor treating you has found an infection and thus has a first suspicion of what could have caused the leukocytosis. In the hyperleukocytosis already mentioned, i.e. the case of an extremely increased leukocytosis, further approaches are necessary to find the cause of the leukocytosis.


A leukocytosis must always be examined and treated by a doctor. This disease is a serious illness, which in the worst case can lead to death. As a rule, however, the underlying disease that is responsible for the leukocytosis must also be treated. However, the further complications and symptoms of this disease depend very much on the severity of the disease and its cause.

For this reason, it is not possible to make a general prediction about the further course. In severe cases, those affected suffer from leukemia and are extremely restricted in their everyday lives. The patients may also be dependent on the help of other people in their everyday life. The quality of life of those affected is also significantly reduced by leukocytosis.

In many cases, however, it is not possible to treat the underlying disease, so that only the symptoms can be limited. The patients are dependent on lifelong therapy, which should make their everyday life easier. It may also result in a reduced life expectancy for those affected. In the case of a long-term illness, there can also be consequential damage.

When should you go to the doctor?

With general symptoms of illness such as fever, it is not absolutely necessary to go to the doctor. However, if the symptoms persist longer than usual or even get worse over time, medical advice is required. If there is already a concrete suspicion of leukocytosis, the nearest doctor’s office must be consulted. Severe infection and symptoms of tuberculosis indicate advanced disease that should be treated promptly.

If the leukocytosis remains untreated, this can lead to complications and, in the worst case, to the death of the patient. For this reason, the warning signs described should be taken seriously, even if there is no concrete suspicion of leukocytosis. It is best for those affected to consult their family doctor immediately, who can make the diagnosis and initiate further measures. Depending on the findings and symptoms, the doctor will consult other specialists for therapy. Typically, leukocytosis is treated by internists, dermatologists, cardiologists, and hematologists. Children must be presented to a pediatrician if they have these symptoms.

Treatment & Therapy

Precisely because leukocytosis is not actually a disease, a (slight) increase in the concentration of white blood cells in the blood is not an indication for treatment. Depending on the severity of the leukocytosis, it is crucial to determine the actual cause.

These are usually infections or a side effect of taking anti-inflammatory drugs or just stress. Nevertheless, depending on the duration and severity of the leukocytosis, more serious diseases such as leukemia must be ruled out as a possible cause.

There is no treatment for leukocytosis itself other than treating the underlying disease.

Outlook & Forecast

The prognosis for leukocytosis is based on different factors. Certain types of leukocytosis have a better chance of being cured than others. Acute leukemia is treatable in many cases. If the disease is detected early, the prognosis is good. In general, the chances of survival have increased significantly in recent years. Modern therapies improve the chances of recovery and alleviate the symptoms. As a result, even seriously ill patients can maintain a certain quality of life. Nowadays, the survival time can also be extended for seriously ill people.

The stage of the disease also plays a role. If leukemia has already developed, the chances of recovery are poorer. The decisive factor is how well the therapy works. The age and general condition of the patient also play a role. In the case of untreated acute leukemia, the average survival period is three months. With treatment, 95 out of 100 children and 70 out of 100 adults survive five years.

The prognosis is worse for acute myeloid leukemia, which is fatal in half of the cases. In the event of a relapse, a more aggressive therapy is often chosen. The strenuous procedures can reduce the life expectancy of patients overall. Patients can actively support the therapy by changing their lifestyle and also by paying attention to unusual symptoms that could indicate leukemia.


If at all possible, leukocytosis can be prevented by avoiding the underlying disease as its cause. This is often not possible if, for example, there is an incurable chronic inflammatory disease or the person concerned has to temporarily take anti-inflammatory drugs because of another illness.


The intensity of follow-up care depends on the degree of leukocytosis. Patients with this disorder need lifelong treatment to relieve symptoms and prevent further complications. Early diagnosis and treatment have a very positive effect on the further course of the disease. Those affected should pay particular attention to a healthy lifestyle. This is based on a balanced diet and regular exercise.

You can do that yourself

Leukocytosis does not necessarily have to be treated. If an elevated white blood cell count is found, the most important thing to do is to have the blood tested regularly. In this way, an increase in leukocytosis can be reacted to quickly, for example by changing the medication or by taking appropriate self-help measures.

Sometimes it is enough to reduce stress in everyday life and at work. Changing your diet can also help bring slightly elevated levels back to normal. The same applies to sports or a visit to the sauna, because all measures that reduce stress naturally regulate the proportion of white and red blood cells in the blood.

If the leukocytosis persists for a long period of time, a doctor’s visit is required. There may be a serious underlying cause for the complaints, which must be determined as part of an extensive investigation.

If leukemia is the cause, treatment must be initiated immediately. Since blood cancer is a serious disease, the person affected should also take advantage of therapeutic help in addition to the treatment. It is advisable to support the therapy with the measures suggested by the doctor in order to improve the chance of recovery.


Leukocytosis Guide