When you have cancer, you may be at higher risk for infection. Some cancers and cancer treatments weaken your immune system. This makes it harder for your body to fight off germs such as viruses and bacteria. If you get an infection, it can quickly become serious and be hard to treat. In some cases, you may need to go to the hospital for treatment. So it is important to learn how to prevent and treat any infections before they spread.
How Having Cancer Increases Infection Risk
As part of your immune system, your white blood cells help fight infection. White blood cells are made in your bone marrow. Some types of cancer, such as leukemia, and some treatments including bone marrow transplant and chemotherapy affect your bone marrow and immune system. This makes it harder for your body to make new white blood cells that can fight infection and increases your infection risk.
Your health care provider will check your white blood cell count during your treatment. When levels of certain white blood cells drop too low, it is called neutropenia. Often this is a short-lived and expected side effect of cancer treatment. Your provider may give you medicines to help prevent infection if this occurs. But, you should also take some precautions.
Other risk factors for infection in people with cancer include:
- Medical conditions such as diabetes or COPD
- Recent surgery
Ways to Prevent Infection
There are many things you can do to help prevent infection. Here are some tips:
- Wash your hands often. Hand washing is very important after using the bathroom, before eating or cooking, after touching animals, after blowing your nose or coughing, and after touching surfaces that other people have touched. Carry hand sanitizer for times when you cannot wash. Wash your hands when you get back home after an outing.
- Take care of your mouth. Brush your teeth often with a soft toothbrush and use a mouth rinse that does not contain alcohol.
- Stay away from sick people or people who have been exposed to sick people. It is easy to catch a cold, the flu, chickenpox, the SARS-CoV-2 virus (that causes COVID-19 disease) or other infection from someone who has it. You should also avoid anyone who has had a live virus vaccine.
- Clean yourself carefully after bowel movements. Use baby wipes or water instead of toilet paper and let your provider know if you have any bleeding or hemorrhoids.
- Make sure your food and drinks are safe. Do not eat fish, eggs, or meat that is raw or undercooked. And do not eat anything that is spoiled or past the freshness date.
- Ask someone else to clean up after pets. Do not pick up pet waste or clean fish tanks or birdcages.
- Carry sanitizing wipes. Use them before touching public surfaces such as doorknobs, ATM machines, and railings.
- Guard against cuts. Use an electric razor to avoid nicking yourself while shaving and do not tear at nail cuticles. Also be careful when using knives, needles, and scissors. If you do get a cut, clean it right away with soap, warm water, and an antiseptic. Clean your cut this way every day until it forms a scab.
- Use gloves when gardening. Bacteria and fungi are often in soil.
- Stay away from crowds. Plan your outings and errands for times that are less crowded. Wear a mask when you have to be around people.
- Be gentle with your skin. Use a towel to gently pat dry your skin after a shower or bath, and use lotion to keep it soft. Do not pick at pimples or other spots on your skin.
- Ask about getting a flu shot. Do not get any vaccines without first talking to your provider. You should NOT receive any vaccines that contain a live virus.
- Skip the nail salon and care for your nails at home. Make sure you use tools that have been cleaned well.
Know How to Spot an Infection
It is important to know the symptoms of an infection so you can call your provider right away. They include:
- A fever of 100.4°F (38°C) or higher
- Chills or sweats
- Redness or swelling anywhere on your body
- Headache, stiff neck
- Sore throat
- Sores in your mouth or on your tongue
- Bloody or cloudy urine
- Pain or burning with urination
- Nasal congestion, sinus pressure or pain
- Vomiting or diarrhea
- Pain in your stomach or rectum
Do not take acetaminophen, aspirin, ibuprofen, naproxen, or any medicine that reduces a fever without first talking with your provider.
When to Call Your Doctor
During or right after cancer treatment, call your provider right away if you have any of the signs of infection mentioned above. Getting an infection during cancer treatment is an emergency.
If you go to an urgent care clinic or emergency room, tell the staff right away that you have cancer. You shouldn't sit in the waiting room for a long time because you may catch an infection. Wear a mask when you have to be around people.
Chemotherapy - preventing infection; Radiation - preventing infection; Bone marrow transplant - preventing infection; Cancer treatment - immunosuppression
Freifeld AG, Kaul DR. Infection in the patient with cancer. In: Niederhuber JE, Armitage JO, Kastan MB, Doroshow JH, Tepper JE, eds. Abeloff's Clinical Oncology. 6th ed. Philadelphia, PA: Elsevier; 2020:chap 34.
National Cancer Institute website. Chemotherapy and you: support for people with cancer. www.cancer.gov/publications/patient-education/chemotherapy-and-you.pdf. Updated September 2018. Accessed January 17, 2023.
National Cancer Institute website. Infection and neutropenia during cancer treatment. www.cancer.gov/about-cancer/treatment/side-effects/infection. Updated January 23, 2020. Accessed January 17, 2023.
Review Date 10/25/2022
Updated by: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.