What Causes High Neutrophils in Cats?

If your vet tells you your cat has high neutrophils, you might feel confused or worried. What does it mean? Is it serious? And what should you do next?

This guide explains everything in simple terms—what neutrophils are, why they go up, and how to figure out what’s really going on with your cat’s health.

What Are Neutrophils in Cats?

Neutrophils are a type of white blood cell that helps fight infection and inflammation in your cat’s body. They’re part of the immune system and act as “first responders” when your cat’s body detects a threat like bacteria, injury, or illness.

A blood test (called a CBC or complete blood count) shows how many neutrophils are in your cat’s bloodstream. When those numbers are high, it means the body is reacting to something—but the exact cause needs to be explored.

What Causes High Neutrophils in Cats?

High neutrophils in cats—also called neutrophilia—usually happen when the body is fighting infection, dealing with inflammation, or reacting to stress or disease.

Common causes include:

1. **Infections**

• Bacterial infections: Wounds, abscesses, respiratory or urinary infections can trigger high neutrophils.
• Viral infections: Some viruses cause a secondary bacterial infection, which can push neutrophil counts higher.

2. **Inflammation or Injury**

• Inflammatory diseases: Conditions like pancreatitis, colitis, or arthritis can elevate neutrophils.
• Trauma or surgery: The body sends more neutrophils to heal and protect damaged tissue.

3. **Stress or Excitement (Stress Leukogram)**

• When cats are highly stressed—like during vet visits—their bodies release stress hormones that temporarily raise neutrophil levels.
• This spike is usually short-lived and not a sign of illness.

4. **Cancer (Neoplasia)**

• Some cancers—especially leukemia or tumors—can cause high white blood cell counts, including neutrophils.
• This is less common but serious, and often comes with other signs like weight loss, poor appetite, or weakness.

5. **Autoimmune Diseases**

• In rare cases, the immune system attacks the body’s own tissues, causing chronic inflammation and elevated neutrophils.

6. **Medications**

• Some drugs, especially corticosteroids, can increase neutrophil counts as a side effect.

What Are the Symptoms of High Neutrophils in Cats?

High neutrophils themselves don’t cause symptoms—it’s the underlying condition that affects your cat’s behavior or health.

Watch for signs like:

• Fever
• Lethargy or weakness
• Loss of appetite
• Swelling, wounds, or abscesses
• Vomiting or diarrhea
• Weight loss or changes in grooming

If your cat has high neutrophils and also shows any of these signs, it’s important to find out the cause quickly.

How Is Neutrophilia Diagnosed?

Neutrophilia is diagnosed with a complete blood count (CBC), but further tests are usually needed to find the cause.

Additional tests your vet might recommend:

• Biochemistry panel (to check liver, kidney, and organ health)
• Urinalysis (to detect infection or inflammation in the urinary tract)
• X-rays or ultrasound (to look for tumors, inflammation, or internal problems)
• FIV/FeLV test (to rule out viral diseases)
• Fine needle aspirate or biopsy (if there’s a visible mass or lump)

Your vet will piece together the full picture using these tests and your cat’s symptoms to identify what’s behind the high neutrophils.

Is High Neutrophils in Cats Dangerous?

Not always—sometimes it’s just the body’s normal response to healing or stress. But if neutrophil counts stay high or go up alongside other health changes, it could point to something more serious.

The key is to determine if it’s temporary (like from stress) or ongoing (like from an infection or disease).

How Is It Treated?

Treatment focuses on the root cause of the elevated neutrophils—not the number itself.

Depending on the diagnosis, treatment might include:

• Antibiotics (for infections)
• Anti-inflammatory medications
• Surgery (if a mass or abscess is present)
• Cancer treatment (if a tumor or leukemia is confirmed)
• Supportive care like fluids, nutrition, and rest

Your vet may repeat the bloodwork after treatment begins to check if neutrophil levels are returning to normal.

When Should You Be Concerned?

Be concerned if your cat has high neutrophils AND is showing signs of illness. If the blood test was routine and your cat seems totally fine, your vet may just monitor it for changes.

But if your cat has:

• Fever
• Ongoing weight loss
• Vomiting, diarrhea, or poor appetite
• Visible swelling or wounds
• Chronic inflammation or infection

Then follow-up testing and treatment are likely needed.

Want to Learn More About Cat Health?

Caring for your cat means staying alert to small changes and understanding what lab results mean. Click here to read more expert-backed pet care guides that help you become a more informed and confident cat owner.

Conclusion

High neutrophils in cats usually mean the immune system is responding to infection, inflammation, stress, or illness. While it can be harmless in some cases, it can also be an early sign of something more serious.

With proper testing and care, most causes can be treated effectively. Explore more trusted advice here to keep your cat healthy and well cared for every step of the way.