Neutropenia, pronounced noo-troh-PEE-nee-uh, is a decrease in the number of white blood cells. These cells are the body’s main defense against infection. Neutropenia is common after receiving chemotherapy and increases your risk for infections.

Febrile neutropenia means you have neutropenia and a fever of 38°C or higher. It is usually a complication of cancer treatment. It is a life-threatening condition requiring immediate medical attention.

If you have neutropenia and a fever, you should contact your doctor immediately and go to the nearest emergency department.

There are many causes of neutropenia.

You can have neutropenia from birth — this is known as congenital neutropenia. Mild neutropenia (slightly low neutrophil counts) is normal for many people of African and Middle Eastern origins.

You can develop neutropenia after an infection from a bacteria or fungus, after taking certain medications, due to an allergic disorder, an enlarged spleen or because of problems with your immune system.

Cancer treatment such as chemotherapy is a common cause of neutropenia. Chemotherapy kills your white blood cells, as well as attacking your cancer cells. This can leave you vulnerable to infections.

Congenital neutropenia syndromes are a group of rare disorders present from birth that are characterized by low levels of neutrophils, a type of white blood cell necessary for fighting infections. NIAID supports basic scientific research on the immune system and the nature and development of neutrophils, which may lead to insights for addressing congenital neutropenia syndromes. Congenital neutropenia syndromes are primary immune deficiency diseases (PIDD).

Congenital neutropenia syndromes may also be called congenital agranulocytosis, severe congenital neutropenia, severe infantile genetic neutropenia, infantile genetic agranulocytosis, or Kostmann disease.

Researchers have identified numerous genetic mutations that cause congenital neutropenia syndromes. Generally, mutations that result in congenital neutropenia affect the development, lifespan, or function of neutrophils.

Congenital neutropenia syndromes are inherited through autosomal recessive, autosomal dominant, and X-linked inheritance patterns. The genes linked to these syndromes include the following:

• ELANE
• HAX1
• G6PC3
• GFI1
• CSF3R
• X-linked WAS
• CXCR4
• VPS45A
• JAGN1

In some people, however, the disease-causing mutation of their congenital neutropenia syndrome is unknown.

People with congenital neutropenia experience bacterial infections early in life. These may cause inflammation of the umbilical cord stump, abscesses (or boils) on the skin, oral infections, and pneumonia.

Congenital neutropenia also increases one’s risk for developing myelodysplastic syndromes (MDS), blood disorders that are distinguished by low levels of various blood cells. MDS may progress to a type of blood-cell cancer called acute myeloid leukemia.

Bone marrow and blood tests can measure the levels of various white blood cells to test for deficiencies. A person suspected of having congenital neutropenia also may undergo genetic testing for one of the genetic mutations known to cause the syndromes.

Standard therapy for congenital neutropenia includes injections of granulocyte colony-stimulating factor (G-CSF), an immune-cell-growth molecule that can help restore the function of the immune system. People on G-CSF therapy may have a lower incidence and severity of infections, improving their quality of life, but effects vary. For some individuals, a bone-marrow transplant may be recommended to replace defective immune cells with healthy ones from a donor.

An infection is the invasion and growth of germs in the body, such as bacteria, viruses, yeast, or other fungi. An infection can begin anywhere in the body, may spread throughout the body, and can cause one or more of these signs:

• fever of 100.5 °F (38 °C) or higher or chills
• cough or sore throat
• diarrhea
• ear pain, headache or sinus pain, or a stiff or sore neck
• skin rash
• sores or white coating in your mouth or on your tongue
• swelling or redness, especially where a catheter enters your body
• urine that is bloody or cloudy, or pain when you urinate

Call your health care team if you have signs of an infection. Infections during cancer treatment can be life threatening and require urgent medical attention. Be sure to talk with your doctor or nurse before taking medicine—even aspirin, acetaminophen (such as Tylenol®), or ibuprofen (such as Advil®) for a fever. These medicines can lower a fever but may also mask or hide signs of a more serious problem.

Some types of cancer and treatments such as chemotherapy may increase your risk of infection. This is because they lower the number of white blood cells, the cells that help your body to fight infection. During chemotherapy, there will be times in your treatment cycle when the number of white blood cells (called neutrophils) is particularly low and you are at increased risk of infection. Stress, poor nutrition, and not enough sleep can also weaken the immune system, making infection more likely.

You will have blood tests to check for neutropenia (a condition in which there is a low number of neutrophils). Medicine may sometimes be given to help prevent infection or to increase the number of white blood cells.

Ways to Prevent Infection

Your health care team will talk with you about these and other ways to prevent infection:

• Wash your hands often and well. Use soap and warm water to wash your hands well, especially before eating. Have people around you wash their hands well too.
• Stay extra clean. If you have a catheter, keep the area around it clean and dry. Clean your teeth well and check your mouth for sores or other signs of an infection each day. If you get a scrape or cut, clean it well. Let your doctor or nurse know if your bottom is sore or bleeds, as this could increase your risk of infection.
• Avoid germs. Stay away from people who are sick or have a cold. Avoid crowds and people who have just had a live vaccine, such as one for chicken pox, polio, or measles. Follow food safety guidelines; make sure the meat, fish, and eggs you eat are well cooked. Keep hot foods hot and cold foods cold. You may be advised to eat only fruits and vegetables that can be peeled, or to wash all raw fruits and vegetables very well.

Talking With Your Health Care Team about Infection

Prepare for your visit by making a list of questions to ask. Consider adding these questions to your list:

• Am I at increased risk of infection during treatment? When am I at increased risk?
• What steps should I take to prevent infection?
• What signs of infection should I look for?
• Which signs signal that I need urgent medical care at the emergency room? Which should I call you about?

These cancer-fighting drugs work by killing fast-growing cells in the body—both good and bad. These drugs kill cancer cells as well as healthy white blood cells.

How Do I Know if I Have Neutropenia?

Your doctor or nurse will tell you. Because neutropenia is common after receiving chemotherapy, your doctor may draw some blood to look for neutropenia.

When Will I Be Most Likely to Have Neutropenia?

Neutropenia often occurs between 7 and 12 days after you receive chemotherapy. This period can be different depending upon the chemotherapy you get. Your doctor or nurse will let you know exactly when your white blood cell count is likely to be at its lowest. You should carefully watch for signs and symptoms of infection during this time.

For patients with neutropenia, even a minor infection can quickly become serious. Call your doctor right away if you have:

Fever that is 100.4°F (38°C) or higher for more than one hour, or a one-time temperature of 101° F or higher.

• Chills and sweats.
• Change in cough or new cough.
• Sore throat or new mouth sore.
• Shortness of breath.
• Nasal congestion.
• Stiff neck.
• Burning or pain with urination.
• Unusual vaginal discharge or irritation.
• Increased urination.
• Redness, soreness, or swelling in any area, including surgical wounds and ports.
• Diarrhea.
• Vomiting.
• Pain in the abdomen or rectum.
• New onset of pain.
• Changes in skin, urination, or mental status.

Neutropenia is diagnosed by a blood test. You may need other tests such as a bone marrow test to find out the cause.

Treatment will depend on the cause of your neutropenia, and how severe it is. If you have neutropenia and a bacterial infection, you may need antibiotics.

There is not much you can do to prevent neutropenia from occurring, but you can decrease your risk for getting an infection while your white blood cell count is low.

How can I prevent an infection? In addition to receiving treatment from your doctor, the following suggestions can help prevent infections:

• Clean your hands frequently.
• Try to avoid crowded places and contact with people who are sick.
• Do not share food, drink cups, utensils or other personal items, such as toothbrushes.
• Shower or bathe daily and use an unscented lotion to prevent your skin from becoming dry and cracked.
• Cook meat and eggs all the way through to kill any germs.
• Carefully wash raw fruits and vegetables.
• Protect your skin from direct contact with pet bodily waste (urine or feces) by wearing vinyl or household cleaning gloves when cleaning up after your pet. Wash your hands immediately afterwards.
• Use gloves for gardening.
• Clean your teeth and gums with a soft toothbrush, and if your doctor or nurse recommends one, use a mouthwash to prevent mouth sores.
• Try and keep all your household surfaces clean.
• Get the seasonal flu shot as soon as it is available.

Your doctor or nurse will tell you. Because neutropenia is common after receiving chemotherapy, your doctor may draw some blood to look for neutropenia.

When Will I Be Most Likely to Have Neutropenia?

Neutropenia often occurs between 7 and 12 days after you receive chemotherapy. This period can be different depending upon the chemotherapy you get. Your doctor or nurse will let you know exactly when your white blood cell count is likely to be at its lowest. You should carefully watch for signs and symptoms of infection during this time.

Cancer patients receiving chemotherapy should not sit in a waiting room for a long time. While you are receiving chemotherapy, fever may be a sign of infection. Infections can become serious very quickly. When you check in, tell them right away that you are getting chemotherapy and have a fever. This may be an indication of an infection.