Leukocytosis: Causes, Symptoms & Treatment

If the number of white blood cells found in the blood exceeds normal levels, doctors refer to it as leukocytosis, which in itself is harmless in moderation, but can be a harbinger of the presence of other, more serious diseases.

What is leukocytosis?

The name leukocytosis is derived from the Greek foreign word syllable “leukos,” which translates as “white.” Leukocytosis thus refers to the white blood cells. Human blood consists of a large number 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 to keep the concentration of the individual components in the correct amount. In leukocytosis, this is no longer the case, as the white blood cells are more abundant in the blood than they should be. Normally, the amount of white blood cells present in the body of a healthy person is about 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 vary, ranging from innocuous to precursors of life-threatening diseases. Usually, leukocytosis is caused by a harmless infection. One of the main tasks of white blood cells is namely immune defense. If the immune system registers a pathogenic foreign body that has invaded the body, it is up to the white blood cells, as one of the supporting elements of the non-specific immune defense, to track down and destroy the foreign body. In this respect, it is not surprising if the white blood cell count increases in the context of an infection; in this case, leukocytosis is neither dangerous nor worthy of further investigation. Particularly those affected by chronic inflammatory diseases, such as patients with Crohn’s disease, a chronic inflammation of the intestines, more often have elevated levels of white blood cells in their blood. However, leukocytosis can also be caused by the administration of drugs. It is known that anti-inflammatory agents such as glucocorticoids can unintentionally stimulate the body to produce more white blood cells. Clearly more serious, however, and this is where closer examination of leukocytosis becomes mandatory after all, is the fact that excessive concentrations of white blood cells – like any other type of blood abnormality – can be a possible sign of leukemia, or cancer of the blood.

Diagnosis and progression

Unlike diseases in the strict sense, leukocytosis lacks its own characteristic symptoms. It is inconspicuous to the patient precisely because it does not cause pain or other discomfort. The only way to detect an elevated white blood cell count is by blood test. During this routine examination by a family doctor, the composition of the blood is examined, as well as its composition from the most important components, which includes the white blood cells. If leukocytosis is detected, it depends on various factors whether further examinations need to be initiated. If the white blood cell count is slightly elevated, the physician will take this as an opportunity to perform another blood test at the next visit to determine whether the slight leukocytosis was only temporary and the blood count has returned to normal. The same also applies if the attending physician has detected an infection and thus has an initial suspicion of what may have caused the leukocytosis. In the case of hyperleukocytosis already mentioned, i.e., the case of extremely elevated leukocytosis, further approaches become necessary to find the cause of the leukocytosis.


Leukocytosis must always be examined and treated by a physician. This is a serious disease that, in the worst case, can lead to death. As a rule, however, the underlying disease 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, a general prediction about the further course is not possible.In severe cases, those affected suffer from leukemia and are extremely restricted in their daily lives. Patients may thus also be dependent on the help of other people in their daily lives. The quality of life of those affected is also considerably reduced by leukocytosis. In many cases, however, treatment of the underlying disease is not possible, so that only the symptoms can be limited. Patients are dependent on lifelong therapy to make their daily lives easier. This may also result in a reduced life expectancy for the affected person. In the case of a protracted disease, consequential damage may also occur.

When should one go to the doctor?

With general symptoms of the disease, such as fever, it is not yet mandatory to go to the doctor. However, if the symptoms persist longer than usual or even become stronger in the course, medical advice is required. If there is already a concrete suspicion of leukocytosis, the nearest doctor’s office must be visited. Severe infections and symptoms of tuberculosis indicate an advanced disease that should be treated immediately. If the leukocytosis remains untreated, this can lead to complications and, in serious cases, to the death of the patient. For this reason, the warning signs described should be taken seriously, even if there is not yet any 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 symptom picture, the physician will consult other specialists for therapy. Typically, leukocytosis is treated by internists, dermatologists, cardiologists and hematologists. Children must be presented to a pediatrician if symptoms are mentioned.

Treatment and therapy

Precisely because leukocytosis is not a disease in the strict sense, a (slight) increase in the white blood cell concentration in the blood is not an indication for treatment. The decisive factor, depending on the severity of the leukocytosis, is to determine the actual cause. These are usually infections or a side effect due to the administration of anti-inflammatory drugs or simply stress. But nevertheless, depending on the duration and severity of leukocytosis, more serious diseases such as leukemia must be ruled out as a possible cause. Except for treatment of the underlying disease, there is no treatment for leukocytosis itself.

Outlook and prognosis

The prognosis for leukocytosis is based on a variety of factors. Different types of leukocytosis have a better chance of cure than others. Acute leukemia is treatable in many cases. If the disease is detected early, the prognosis is good. In general, survival prospects have increased greatly in recent years. Modern therapies improve the chances of cure and alleviate symptoms. As a result, even seriously ill patients can retain a certain quality of life. Nowadays, survival time can be extended even in severely ill people. The stage of the disease also plays a role. If leukemia has already developed, the prospects 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 untreated acute leukemia, survival averages three months. With treatment, 95 out of 100 children and 70 out of 100 adults survive for five years. The prognosis is worse in acute myeloid leukemia, which is fatal in half of cases. In the event of a relapse, more aggressive therapy is often chosen. Strenuous procedures can worsen patients’ overall life expectancy. Patients can actively support therapy by making lifestyle changes and also by watching for unusual symptoms that may indicate leukemia.


Leukocytosis can be prevented, to the extent that this is at all possible, by avoiding the underlying disease as its cause. Often this is not possible if, for example, there is an unhealthy inflammatory disease of a chronic nature or if the affected person has to take anti-inflammatory drugs temporarily because of an illness elsewhere.


Depending on the degree of severity of leukocytosis, the intensity of follow-up depends.Affected individuals rely on lifelong treatment for this disorder to alleviate symptoms and prevent further complications. Early diagnosis and treatment have a very positive effect on the further course of the disease. Patients should pay particular attention to a healthy lifestyle. This is directed towards a balanced diet and regular exercise.

What you can do yourself

Leukocytosis does not necessarily need to be treated. If an increased level of white blood cells has been detected, the most important measure is to have the blood tested regularly. In this way, if the leukocytosis increases, it is possible to react 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. A change in diet can also help to bring slightly elevated values back to a normal level. So can 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 over a longer period of time, a visit to the doctor is necessary. It is possible that there is a serious cause underlying the symptoms, which must be determined in the course of an extensive examination. If the cause is leukemia, treatment must be initiated immediately. Since blood cancer is a serious disease, the affected person should also seek therapeutic help to accompany the treatment. It is indicated to support the therapy with the measures suggested by the physician to improve the chance of recovery.