If you or a loved one has chronic lymphocytic leukemia (CLL) or another type of leukemia, you may have heard of or experienced cold- or flu-like symptoms known as B symptoms — night sweats, fever, and unintentional weight loss. This group of symptoms is commonly associated with lymphomas but can occur in CLL and other blood cancers too.

Because B symptoms overlap with those of common illnesses like a cold or the flu, they can be difficult to identify. Especially if you’re in a period of watchful waiting — keeping an eye on your condition but not treating it — it’s important to monitor for B symptoms. The symptoms could be a sign that your cancer is progressing. B symptoms don’t always indicate a relapse, but only your doctor can determine what they mean and whether you need immediate treatment.

Read on to learn how to spot B symptoms and when it’s time to talk to your doctor.

What Are B Symptoms?

B symptoms are a group of symptoms commonly associated with lymphomas, both Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). B symptoms can occur with CLL and other types of leukemia, as well as other blood cancers.

B symptoms include:

• Fever — Having a body temperature over 100.4 degrees Fahrenheit (38 degrees Celsius) for no apparent reason
• Sweating a lot at night — Sometimes drenching clothes or sheets
• Significant, unintentional weight loss — Dropping more more than 10 percent of your body weight in the previous six months

These and other symptoms (such as enlarged lymph nodes) can overlap with those of the common cold or other illnesses, and they may not be connected with leukemia. Even so, symptoms that persist should be discussed with your doctor.

What MyLeukemiaTeam Members Say About B Symptoms

Many MyLeukemiaTeam members have described having night sweats:

• “I wake up wet all the time from night sweats. It wrecks my day because it’s a constant reminder I have CLL. I also get the chills sometimes.”
• “I sweat at night a lot, then throughout the day, I need a sweater. I look and feel a mess.”
• “Out of nowhere, I have the sweats, fatigue, and seem to get brain fog a lot lately.”

Unintended weight loss is also a common topic:

• “I have done nothing but lose weight since before I was diagnosed. I have to make myself eat.”
• “I lost 35 pounds before being diagnosed and still have a hard time having an appetite, but I’m trying to!”
• “I’ve lost 18 pounds since discovering I have CML [chronic myeloid leukemia], a 9 percent loss. Is this a normal rate of weight loss for people with leukemia? And when does the weight loss stabilize?”

Some members also discussed how B symptoms seem to come and go. “Mostly I just wake up drenched in sweat and feeling terrible. Yesterday was an awful day. All day long I felt like I was coming down with something, then during the night I was drenched in sweat and feel better today,” one member wrote. “It just blindsides you!”

Members also discuss how these cold- and flu-like symptoms are a common part of living with leukemia. “When I was diagnosed earlier this year, my oncologist outright told me that I could experience profuse night sweats, utter fatigue, and any number of other symptoms,” one member shared.

Although it’s common to experience B symptoms, it’s still important to talk with your doctor about them. They can help you understand if and when B symptoms should be reported right away and if you should be monitored for changes.

What Do B Symptoms Mean?

B symptoms may be early symptoms of both lymphocytic leukemia and lymphomas. However, symptoms of chronic leukemia, such as CLL or chronic myeloid leukemia, may not show up until years after the disease starts, so B symptoms aren’t reliable indicators of cancer.

When symptoms, including B symptoms, do appear, watchful waiting may be the next step. Doctors and oncologists (cancer specialists) may recommend a “watch and wait” approach based on factors like genetic mutations of cancer cells or overall prognosis (likely outcome). The purpose of watchful waiting is to avoid using aggressive treatment for CLL or other types of leukemia in people who aren’t at high risk of progression. Also, B symptoms can mimic the common cold, so it can be beneficial to not jump to conclusions about a diagnosis or relapse.

Nonetheless, B symptoms sometimes indicate that it’s time to start targeted therapy. For example, the authors of a 2023 study wrote that people with CLL who had “fever, drenching night sweats, and weight loss (B symptoms) should be offered treatment.” According to the Leukemia & Lymphoma Society, B symptoms are important indicators of the prognosis and stage of non-Hodgkin leukemia — CLL and small lymphocytic leukemia are types of NHL.

If you’re having B symptoms that persist, it’s best to speak with your doctor or oncologist. They may do some blood tests to look for any changes in disease progression and decide whether your treatment plan needs to be adjusted.

How To Tell if You Have a Virus or B Symptoms

It may be frightening to develop cold or flu symptoms when you know some overlap with leukemia symptoms. However, a few details can help you differentiate between a virus and leukemia and decide if you should speak with your doctor.

One important thing to keep in mind is the duration of symptoms. For example, most colds go away in a week to 10 days. If your B symptoms last longer than that, talk to your doctor.

Taking note of other kinds of symptoms can also help distinguish a viral infection from leukemia. For example, CLL symptoms that you would likely not experience with the common cold include:

• Feeling unusual fullness or stomach pain, which may be due to an enlarged spleen or liver
• Getting bruised easily or developing bleeding gums or frequent nosebleeds, which may indicate thrombocytopenia (low platelet count )
• Feeling extremely tired or weak or short of breath, which may be a sign of anemia (low red blood cell count)

These symptoms are due to leukemia’s effects on the bone marrow, where blood cells are produced. If you have any of the above symptoms with or without B symptoms, be sure to report them to your doctor.

How To Manage B Symptoms at Home

You might be able to manage B symptoms at home, but first discuss your plan with your doctor. It’s important to make sure that any over-the-counter medications you might take won’t interact with prescribed treatments for leukemia or other conditions.

To manage fever at home, try:

• Checking your temperature every two to three hours and noting the number
• Drinking plenty of fluids
• Placing a cold compress on your forehead
• Getting adequate rest

Fever-reducing medications may also be an option, but check with your doctor before taking them.

Staying well rested is important for managing B symptoms and other symptoms of leukemia, but it can be difficult to get quality sleep when you have night sweats. The following changes to your sleep environment may help manage night sweats:

• Use cotton or sweat-wicking sheets.
• Turn on an air conditioner or a fan.
• Keep your bedroom between 60 and 67 degrees.

Some MyLeukemiaTeam members have reported success with running a fan at night to reduce night sweats. One member wrote, “A good fan and AC really help. I’ve been dry during the night, which is great!” Another shared, “Sweats have basically stopped, but I still sleep with a fan on.”

Significant weight loss may be difficult to address because of other symptoms, such as losing your appetite or sense of taste or quickly feeling full. One member shared that their weight loss was “mainly because everything tasted like cardboard, and I was too tired to eat.” You might lose weight even if you eat normally. Be sure to reach out to your doctor if you’re having trouble keeping weight on.

If you have questions about managing B symptoms at home, talk with your doctor or oncologist. They may be able to recommend treatment options unique to your circumstance so that living with B symptoms is less of a drain on your quality of life.

Find Your Team

MyLeukemiaTeam is the social network for people with leukemia and their loved ones. On MyLeukemiaTeam, more than 14,000 members come together to ask questions, give advice, and share their stories with others who understand life with leukemia.

Are you living with CLL or another type of leukemia and experiencing B symptoms? Have you found effective ways to manage B symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.