18 Unbelievable Reasons Behind Your Skyrocketing Neutrophil Count

Neutrophilia is a condition characterized by an excessive number of neutrophils in the bloodstream. As the body’s first line of defense against infections, neutrophils make up 40-60% of all white blood cells. In a healthy individual, neutrophil counts typically range between 2,500 and 7,500 per microliter of blood. When this balance is disrupted, neutrophilia can develop, signaling an underlying issue. To provide a clearer understanding, we have expanded our list to 18 key causes of neutrophilia, categorizing them into three primary groups. Reactive neutrophilia occurs in response to infections or stress, proliferative neutrophilia results from excessive production in the bone marrow, and demargination happens when neutrophils detach from blood vessel walls and remain in circulation. Treatment varies depending on the cause, ranging from antibiotics for infections to chemotherapy for leukemia or targeted therapies for autoimmune conditions. Identifying the root cause is crucial in determining the most effective treatment plan.

1. Arthritis

Individuals affected by arthritis may develop neutrophilia as a result. Neutrophils are the main type of white blood cell that contributes to the trigger and progression of arthritis. They play this role by releasing molecules that are toxic to other living cells in the body and molecules that mediate responses between macrophages and lymphocytes. Neutrophils in arthritis patients have different cellular properties than those in healthy individuals. Rheumatoid arthritis patients have neutrophils with delayed cellular death and a more sophisticated ability to generate reactive oxygen species, activate and deactivate certain genes, and expression of high-affinity FcY receptors on the cell membrane. These patients also have an immune system that exhibits a defect in their function of neutrophil clearance. In some autoimmune disorders, neutrophils may be the point of supply of the specific autoantigens or antibodies that propel the underlying mechanisms that result in the autoimmune disease. It is a combination of neutrophil apoptosis delay, clearance defects of neutrophils, and other abnormal properties of neutrophils that can cause an individual with arthritis to also be affected by neutrophilia.

2. Certain Forms Of Leukemia

An individual's neutrophilia can be caused by certain forms of leukemia. Chronic myeloid leukemia is a type of cancer that begins in bone marrow or blood-forming tissues. In the beginning stages of this type of leukemia, the bone marrow produces an excess amount of white blood cells. However, myeloblasts or immature white blood cells begin to accumulate in the patient's bone marrow and blood. This results in a decreased red blood cell and platelet production. Acute myeloid leukemia also causes neutrophilia, but on a much quicker timeline than its chronic form. Myelofibrosis is a chronic form of leukemia where a patient's bone marrow is replaced by scar tissue, resulting in too many red and white blood cells that do not fully mature and cannot function as healthy cells. Chronic neutrophilic leukemia is a slow-growing cancer of the bone marrow where it makes too many neutrophils. Acute neutrophilic leukemia also causes neutrophilia, but grows at a much faster rate.

3. Infections

Certain infections, such as those resulting from streptococci, pneumococci, and Escherichia coli bacteria, are known to trigger neutrophilia. Fungal infections known to cause it stem from the fungi known as Candida albicans and coccidiosis immitis. Viral infections that cause this condition include rabies, herpes zoster, varicella, poliomyelitis, and smallpox. Parasites can also cause this condition, but typically less often than viruses and bacteria. An individual who has an abscess, appendicitis, meningitis, and tonsillitis can also experience neutrophilia due to their infection. Since neutrophils are the first white blood cells in the immune system to reach the site of cellular damage, they can be overproduced in patients when their infection induces such a reactive process in the body. A mild elevation in these blood cells during acute infection is beneficial. However, anything greater can cause the blood to become too thick and produce serious complications.

4. Removal Of The Spleen

An individual who has undergone removal of their spleen may develop neutrophilia as a complication. The spleen and liver can produce certain blood cells when the bone marrow is not making enough. At the same time, the spleen is a key component in the process of neutrophil removal and destruction of dead and dying neutrophils from the body. There are only three tissues in the body that can perform neutrophil clearance. They are the spleen, liver, and bone marrow. All three of these contribute to the clearance process equally in most healthy individuals. However, some individuals have had to have their spleen removed due to several conditions and diseases. Without the spleen, the liver and bone marrow are left to perform the job of clearing out neutrophils marked for apoptosis and destruction. The removal of the spleen requires at least a minimally invasive procedure that results in post-operation inflammation. This process causes an increase in the production of neutrophils, with only two-thirds of the healthy neutrophil clearance functionality left. Neutrophilia is often the result of this mechanism.

5. Reaction To Certain Medications

An individual's reaction to certain medications can cause them to develop neutrophilia. Beta-adrenergic agonists are bronchodilators, which loosen the muscles lining an individual's airways. These medicines are typically used to treat individuals with bronchitis, asthma, emphysema, and other lung conditions. Neutrophilia is an uncommon adverse side effect of these medications. Corticosteroids exhibit a similar mechanism that causes neutrophilia. However, they are typically used to treat other issues, such as autoimmune disorders, skin conditions, and to prevent organ transplant rejection. Epinephrine is used to treat anaphylaxis, cardiac arrest, and other emergent conditions. This medicine causes the neutrophils embedded in the blood vessel walls to enter and populate the bloodstream, resulting in neutrophilia. Granulocyte colony-stimulating factor is a medication used in cancer patients who have a low neutrophil count following their treatment. This medication stimulates the production and release of white blood cells from the bone marrow. Thus, it may cause neutrophilia. Heparin can cause neutrophilia because it causes increased activation of neutrophilic components. Lithium, a medication used to treat some psychiatric disorders, is also known to cause neutrophilia. It does this by stimulating the production and release of neutrophils from the bone marrow.

6. Heart Attack

A major factor in neutrophilia development is acute inflammation. This is a significant reason why a heart attack, which causes acute inflammation, can trigger neutrophilia in quite a few patients. A heart attack, of course, is the result of blood flow to the individual's heart being blocked. In many instances, the blockage is from a buildup of cholesterol, fat, and similar substances. The buildup causes plaque in the coronary arteries. Plaque can also rupture and form a blood clot that also blocks blood flow. Symptoms of a heart attack include chest pain and pressure, tightness in the chest, nausea, heartburn, indigestion, and shortness of breath. Individuals who think they may be having a heart attack need emergency medical attention.

7. Burns

Many patients will deal with neutrophilia after experiencing a burn, such as a burn due to excessive heat from liquids, a chemical burn, and an electrical burn. First-degree burns, which are those that result in minimal damage to the skin, do not often trigger neutrophilia. They are superficial burns and heal within seven to ten days. Individuals are more likely to experience neutrophilia due to the acute inflammation from second- or third-degree burns, which is more serious. Patients may be able to treat some second-degree burns at home, but may need the hospital. Third-degree burns do require prompt medical attention, and often patients need surgery. The extended healing time from second- and third-degree burns is often what increases the risk of neutrophilia, since inflammation sticks around as well.

8. Stress

Stress is a significant cause of reactive neutrophilia. This is because stress hormones in the body, which increase when individuals are experiencing stress, cause the release of a higher than normal amount of neutrophils from the individual's bone marrow. Reactive neutrophilia is more likely to occur in response to chronic stress rather than a single day or a few hours of an individual dealing with more stress than usual. Chronic stress puts significant pressure on an individual's body for an extended period and makes it hard for them to function normally. Symptoms of chronic stress include frequent headaches, constant fatigue, increased irritability, low self-esteem, appetite changes, sleeping problems, and concentration issues.

9. Surgery

Surgery, even simple and routine surgeries, come with certain risks. One of the most common risks for patients is an infection after surgery, such as around the surgical incision. Unfortunately, this can happen even when the surgeon performs very well in the sterile environment. Infections are also a risk after the patient leaves the hospital and the incision has not completely healed. Infections will trigger an immune response, which can mean that an individual's white blood cell count rises, causing neutrophilia in some instances. In addition, it is also vital to note that a patient's white blood cell count will rise during surgery. This is the body's natural immune response to the abnormal event of surgery. When the surgery is clean and successful, these cells simply clean up dead tissue and things will return to normal after the surgery is over and during recovery. However, this response can sometimes remain, triggering neutrophilia.

10. Injury

Injuries, especially those that cause significant tissue damage and bruising, increase the risk of individuals experiencing neutrophilia. One of the major reasons this happens is that the body will respond to the injury with inflammation. Inflammation signs, of course, include pain, redness, warmth, and swelling. Neutrophils are part of the immune response to an injury. In fact, neutrophils are the first white blood cells to respond to an injury. They are the cells that release chemical signals to attract other immune cells to the injury. The intent is to heal and protect the injury. However, serious injuries can result in extended periods of inflammation, and thus, neutrophilia.

11. Smoking

Cigarette smoking has a profound effect on the immune system, and one of its lesser-known consequences is neutrophilia. Research has shown that chronic smokers tend to have higher white blood cell counts, including an excess of circulating neutrophils. This occurs because smoking introduces harmful chemicals into the lungs, triggering a constant low-level inflammatory response. Neutrophils, as part of the body's first line of defense, are continuously produced in greater numbers to combat the perceived threat. Over time, this persistent inflammation can contribute to chronic lung conditions such as chronic obstructive pulmonary disease (COPD) and increase the risk of cardiovascular disease. Interestingly, former smokers often experience a gradual decrease in neutrophil levels after quitting, as the body begins to recover from inflammation. The link between smoking and elevated neutrophil counts highlights yet another reason to consider quitting—beyond lung health, it directly impacts overall immune system function and long-term well-being.

12. High-Altitude Exposure

People who travel to or live at high altitudes may experience a condition known as altitude-induced neutrophilia. At higher elevations, oxygen levels decrease, which triggers a physiological response in the body to compensate. One of these responses includes an increase in red blood cell production to carry more oxygen. However, studies have also shown that white blood cell counts, particularly neutrophils, tend to rise in individuals exposed to high altitudes for extended periods. This is believed to be due to mild, sustained hypoxia (low oxygen levels), which places stress on the body and stimulates the bone marrow to produce more neutrophils. In some cases, this effect can persist for weeks or months after prolonged high-altitude exposure, especially in climbers, hikers, and residents of mountainous regions. While generally not harmful on its own, altitude-related neutrophilia is an intriguing example of how environmental factors can influence immune function.

13. Chronic Sleep Deprivation

A good night's sleep does more than just help you feel rested—it plays a critical role in regulating immune function. Studies have found that chronic sleep deprivation can lead to increased neutrophil counts, a lesser-known consequence of poor sleep habits. When the body is consistently deprived of rest, it experiences a heightened stress response, leading to the release of stress hormones such as cortisol. These hormones signal the bone marrow to produce more neutrophils, resulting in a form of low-grade inflammation that persists over time. Individuals who regularly get insufficient sleep may not only experience fatigue and cognitive issues but also unknowingly alter their immune system balance. Interestingly, once proper sleep patterns are restored, neutrophil levels tend to return to normal. This highlights the importance of quality sleep in maintaining immune health and preventing unnecessary inflammatory responses in the body.

14. Extreme Exercise and Overtraining

While regular exercise is widely recognized as beneficial for immune function, excessive physical exertion—especially among elite athletes or individuals engaging in extreme endurance training—can actually trigger neutrophilia. When the body undergoes intense physical stress, muscle fibers experience microscopic damage, and the immune system responds by increasing neutrophil production to aid in tissue repair. This effect is particularly pronounced in marathon runners, triathletes, and those who engage in prolonged high-intensity workouts. Additionally, overtraining without adequate recovery can lead to chronic inflammation, keeping neutrophil levels elevated for extended periods. While exercise-induced neutrophilia is usually temporary and not harmful, persistent overtraining without proper rest can compromise immune function, making individuals more susceptible to infections and fatigue. Balancing high-intensity training with proper recovery periods is key to maintaining a healthy immune response.

15. Obesity and Metabolic Syndrome

Excess body fat, particularly visceral fat around the organs, is not just a passive storage site—it actively releases inflammatory molecules that contribute to chronic low-grade inflammation in the body. This inflammatory state stimulates the bone marrow to produce more neutrophils, leading to neutrophilia in some individuals with obesity or metabolic syndrome. Metabolic syndrome, a cluster of conditions that includes high blood pressure, insulin resistance, and abnormal cholesterol levels, is strongly associated with increased neutrophil counts. Research suggests that chronic inflammation in overweight individuals may contribute to the development of type 2 diabetes and cardiovascular disease. The good news is that weight loss and improved metabolic health through lifestyle changes—such as better diet, exercise, and stress reduction—can help lower neutrophil levels, reducing the risk of long-term complications.

16. Periodontal Disease (Gum Infections)

Your oral health and immune system are more closely linked than you might think. Periodontal disease, a severe form of gum infection caused by bacteria, can lead to persistent neutrophilia. When bacteria accumulate along the gum line, they trigger an immune response, recruiting neutrophils to the site of infection. If left untreated, the infection becomes chronic, leading to ongoing inflammation and an excess of circulating neutrophils in the bloodstream. Studies have shown that individuals with advanced periodontal disease often exhibit elevated white blood cell counts, including neutrophils, even if they do not have other obvious signs of systemic illness. Regular dental check-ups, proper oral hygiene, and treating gum disease early can help prevent prolonged immune activation and its associated risks, including heart disease and diabetes.

17. Pregnancy

Pregnancy is associated with natural changes in the immune system, including mild neutrophilia. During pregnancy, the body undergoes hormonal shifts that alter blood composition, including an increase in white blood cell production. Neutrophils rise gradually throughout pregnancy, particularly in the third trimester, as the body prepares for labor and delivery. This increase is considered a normal physiological adaptation and does not indicate an infection or underlying disease unless accompanied by other symptoms. However, in some cases, gestational neutrophilia can be more pronounced if there are additional factors at play, such as an infection, stress, or pre-existing inflammatory conditions. Postpartum, neutrophil levels typically return to normal within a few weeks. While pregnancy-related neutrophilia is not a cause for concern in most cases, monitoring blood counts during prenatal visits helps ensure maternal and fetal well-being.

18. Allergic Reactions and Anaphylaxis

While allergies are typically associated with an increase in eosinophils (another type of white blood cell), severe allergic reactions can also trigger neutrophilia. During an allergic response, the immune system releases histamines and inflammatory cytokines, leading to increased production and mobilization of neutrophils. In cases of anaphylaxis, a life-threatening allergic reaction, neutrophils may be rapidly deployed to help counteract widespread inflammation and tissue damage. Additionally, chronic allergic conditions such as allergic asthma and hay fever can contribute to mild, persistent neutrophilia due to ongoing immune activation. Understanding how allergic responses influence white blood cell levels can help individuals manage their symptoms more effectively and seek appropriate treatment when necessary.

Understanding Neutrophilia: A Key to Better Health

Neutrophilia is a complex condition with a wide range of causes, from infections and chronic inflammation to lifestyle factors and physiological changes. While elevated neutrophil levels can sometimes signal a serious underlying condition, they can also result from natural bodily responses, such as stress, exercise, or pregnancy. Understanding what triggers neutrophilia is essential for accurate diagnosis and effective treatment. In many cases, addressing the root cause—whether through managing an infection, reducing stress, or making lifestyle adjustments—can help restore balance to the immune system. If neutrophilia is detected in routine bloodwork, it’s important to work with a healthcare professional to determine the cause and appropriate course of action. By recognizing both common and lesser-known contributors to this condition, individuals can take proactive steps toward maintaining optimal health. Awareness and timely intervention can make all the difference in ensuring that an elevated neutrophil count leads to answers, not unnecessary alarm.