Is a Persistent Low-Grade Fever a Symptom of Cancer?

Learn how cancer-related fevers differ from typical fevers

nurse checking for fever
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A fever is an extremely common symptom that's related to many conditions, most of which are benign. An increase in body temperature is most often a biological response to a viral or bacterial infection (like if you're experiencing a cough or congestion). The body simply raises its temperature to help destroy the invading germ.

But what if you're not fighting off a cold?

How a Fever Can Be Related to Cancer

In some cases, a persistent and otherwise unexplained fever ​can be related to cancer.

​​Leukemia and ​lymphoma, for example, are two types of cancer that are commonly known to cause fevers. Leukemia is cancer of the blood-forming tissues in the body. Lymphoma is a cancer of the lymphatic system (which is part of the immune system). One type is called Hodgkin (or Hodgkin's) disease and the other types are called non-Hodgkin lymphomas.

What Cancer-Related Fevers Are Like

These are the key signs of a cancer-related fever:

  • It's a persistent fever, meaning it lasts longer than three days.
  • It can be accompanied by other symptoms or it can occur without other symptoms. Other common symptoms of leukemia include fatigue, weakness, frequent infections, abdominal bruising or excessive bleeding, bone and joint pain, enlarged lymph nodes, abdominal discomfort, and headaches. Other common symptoms of lymphoma include unexplained rapid weight loss, excessive sweating at night, itchiness all over the body, loss of appetite, weakness, breathlessness, and swelling of the face and neck.
  • It can be either a low- or high-grade fever, so don't brush off a persistent, low-grade fever just because it isn't high.

If your low-grade or high-grade fever is very persistent, it's important to see your doctor to determine the cause of the fever. Keep an eye on your temperature regularly by using a thermometer.

Even if over-the-counter fever reducers like acetaminophen or ibuprofen relieve your fever, it's still critical to see your physician if the fever lasts for more than three days.

What to Expect at the Doctor

Unexplained fevers can be caused by a myriad of conditions, and your doctor will likely ask a lot of questions to help make an accurate diagnosis, such as:

  • How long have you had the fever?
  • Do you have any other symptoms?
  • What medications are you taking?
  • Do you suffer from any diseases or conditions?
  • How often do you have a fever? Do you notice it more at night?
  • Do you have a dental abscess or other dental problems that may have an infection?
  • Have you traveled to any other countries within the last few months?

Your doctor may decide to do a few routine tests, such as a complete blood count (CBC) or a chem 7 panel to see what they reveal. He or she may also want to do a urinalysis to rule out a urinary tract infection as the cause.

Don't Panic

Keep in mind that a fever is a very general, vague symptom of cancer. It's not a red flag, but more of an indication to your doctor to run certain medical tests. 

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