Febrile Neutropenia: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Febrile Neutropenia?
An oncologist, a doctor who treats cancer, usually manages febrile neutropenia, because it most often follows chemotherapy. An emergency doctor often treats it first, since a fever with low white blood cells needs care right away. Contact your cancer care team first. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is febrile neutropenia?
Febrile neutropenia (FN) means you have a fever and a low white blood cell count. It is also called neutropenic fever. Neutropenia means you do not have enough neutrophils, a kind of white blood cell, to fight off infection.
For people with cancer, a fever is a temperature of 100.4°F (38°C) or higher for at least one hour. Infections can become life-threatening very quickly when you have neutropenia.
Symptoms
Neutropenia itself does not usually cause signs or symptoms. A fever may be the only sign of infection. Other signs of infection can include:
- Chills and sweats.
- Fast heartbeat.
- Breathing problems or cough.
- Dizziness or lightheadedness.
- New or worse confusion.
- Sore throat, or sores or white patches in the mouth.
- Pain or burning when you pee.
- Redness, swelling or sores on the skin, especially around a catheter, tube or drain.
When you are neutropenic, you might not have the usual signs. You might not have chills, sweats or a cough. Some people with severe neutropenia have no signs of infection at all. Some even have a lower-than-normal body temperature.
Causes and who gets it
People with cancer have a higher risk of infection because many cancer treatments can lower white blood cell counts. White blood cells fight infection. Neutropenia can be caused by cancer, cancer treatments such as chemo, or something not related to cancer.
Other causes include cancers that affect the bone marrow, such as leukemia, lymphoma and multiple myeloma. Targeted drug therapy and stem cell transplants can also cause it. So can many infections, including COVID-19 and HIV, and immune conditions such as lupus.
After chemo, the lowest white blood cell count is called the nadir. It usually happens about 7 to 10 days after chemo. This is when a person is most at risk for a severe infection.
How doctors diagnose it
Your cancer team may check your white blood cell counts with blood tests. A complete blood count with differential counts the types of white blood cells. Blood cultures check for germs in the blood. Doctors may also test body fluids, such as stool, urine or sputum, and may use imaging scans such as an x-ray.
Treatment
If you have signs of infection and a low white blood cell count, you might be started on treatment before the cause is known. Antibiotic, antiviral and antifungal medicines are often given when someone has a low white blood cell count and a fever.
Growth factor medicines help the bone marrow make more white blood cells. They are also called G-CSFs and are usually given as a shot. If chemo is causing neutropenia, the treatment might be lowered, switched, or held off until your body recovers.
Ask your cancer care team before taking any fever medicine, such as Tylenol. They might want you to avoid treating the fever. Never place a thermometer in your rectum if you are neutropenic.
When to see a doctor
Take your temperature any time you feel warm, flushed, chilled or not well. Call your doctor immediately if you have a temperature of 100.4°F (38°C) or higher. A fever can be life-threatening, so you should be seen quickly. If you cannot reach your care team right away, go to the emergency room. Always keep your doctor's phone number nearby. Know which number to call when the office is open and when it is closed.
Get medical help right away if you have chills or sweating, new or worsening confusion, or dizziness. If you go to the emergency room, say that you are a cancer patient on chemotherapy.
Call 911 or go to the emergency room if you faint, have chest pain, have trouble breathing, have a seizure, or cannot be woken up.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. This kind of doctor can help you plan what to do if a fever starts and can coordinate with your cancer team. A fever during chemotherapy still needs urgent care from your cancer team or an emergency room.
Common questions
What temperature counts as a fever with chemotherapy?
For people with cancer, a fever is 100.4°F (38°C) or higher for at least one hour. Call your doctor immediately if your temperature reaches 100.4°F (38°C) or higher.
Is febrile neutropenia an emergency?
Yes, it is. Infections can become life-threatening very quickly in people with neutropenia. Call your doctor right away.
Can I take medicine to bring down the fever?
Not until you ask your care team. They might want you to avoid treating the fever, so check before taking medicine such as Tylenol.
Can a person have neutropenia without a fever?
Yes. Neutropenia itself does not usually cause signs or symptoms. A fever may be the only sign that an infection has started.
Sources
- American Cancer Society - Fevers
- American Cancer Society - Neutropenia (Low White Blood Cell Counts)
- Centers for Disease Control and Prevention - Watch Out for Fever
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
