Are Night Sweats a Sign of Cancer?

Medically reviewed by Tim Legg PhD, PMHNP-BC, GNP-BC, CARN-AP, MCHES on July 5, 2016Written by Annette McDermott

Night sweats

Sweating is how your body cools itself. It happens to everyone throughout the day, but some people experience episodes of increased sweating at night. Night sweats are more than just breaking a sweat because you have too many blankets on your bed. They cause you, your pajamas, and your bedding to become drenched.

If you have night sweats, your sheets and pillows typically become so saturated that you can no longer sleep on them. Some people describe an episode of night sweats as feeling as if they’ve jumped into a swimming pool. Night sweats may occur even if your room is comfortably cool.

Causes of night sweats

Cancer

Night sweats may be an early symptom of:

It’s unclear why some types of cancer cause night sweats. This may happen because your body is trying to fight the cancer. Hormone level changes may also be a cause. When cancer causes a fever, your body may sweat excessively as it tries to cool down. In some cases, night sweats occur due to cancer treatments such as chemotherapy, drugs that alter hormones, and morphine.

If your night sweats occur due to cancer, you’ll likely experience other symptoms. This includes a fever and unexplained weight loss.

Other causes

Although night sweats are a symptom of some types of cancer, they can also happen for other reasons, such as:

Lifestyle factors that may cause night sweats include:

  • exercising before going to bed
  • drinking hot beverages before going to bed
  • drinking alcohol
  • eating spicy foods close to bedtime
  • setting your thermostat too high
  • a lack of air-conditioning in hot weather

You may be able to reduce or relieve night sweats by pinpointing any triggering lifestyle factors and avoiding them.

Check out: Tips for dealing with menopausal hot flashes and night sweats »

What to expect at your doctor’s appointment

If you’ve only had an episode or two of night sweats, you probably don’t need to see your doctor. Environmental or lifestyle factors are likely causes. You should see your doctor if night sweats occur regularly and disrupt your sleeping habits. You should consult your doctor if you experience fevers, unexplained weight loss, or other symptoms.

When you call to make your appointment, your doctor may ask you to keep a medical diary in the coming days. You should use this diary to track your symptoms. Each time you have a night sweat, be sure to note what you were doing that day, the temperature in your bedroom, and what you ate or drank before going to bed.

At your appointment, your doctor will review your medical history and assess your symptoms. Your doctor may order blood tests to check your thyroid levels, blood sugar levels, and blood cell counts. The results can help them confirm a suspected diagnosis or help rule out an underlying condition.

If you think your night sweats may be a sign of cancer, discuss this with your doctor. Follow these tips to help you have a successful conversation with your doctor:

  • Write down a list of questions or concerns you have ahead of time and bring it to your appointment.
  • Bring a family member or friend with you for support.
  • Take notes during your appointment to help you remember your doctor’s recommendations.
  • If you don’t understand something, ask your doctor to repeat it.
  • Ask your doctor if you can record your conversation.

If you believe your night sweats are occurring due to a medical condition such as cancer, don’t let your doctor brush you off. You should insist that they run tests to find out. If your doctor doesn’t address your concerns or take you seriously, consider getting a second opinion.

How to treat night sweats

How night sweats are treated depends on their cause. Night sweats caused by environmental or lifestyle should go away on their own once you eliminate their triggers. If infection is the cause, your doctor may prescribe antibiotics.

If night sweats occur due to perimenopause or menopause, talk to your doctor about hormone replacement therapy (HRT). Some kinds of HRT may increase your risk of developing serious conditions, such as:

You’ll need to carefully weigh the pros and cons of taking HRT against having night sweats.

If cancer is causing your night sweats, you must get treatment for cancer to treat the night sweats that it causes. Cancer treatments vary by cancer type and stage. Common treatments include surgery, chemotherapy, and radiation. Some cancer treatment drugs may cause night sweats. This includes tamoxifen, opioids, and steroids. As your body adjusts to the treatment, the night sweats may subside.

The off-label use of these drugs may relieve night sweats:

Off-label prescription drug use: What you need to know »

Outlook

Most people experience the discomfort of night sweats at least once, typically with no lasting problems. If you have night sweats regularly, your outlook depends on why you have them. Persistent night sweats are your body’s way of letting you know something may be wrong. Doctors can treat most causes successfully.

If cancer is causing your night sweats, they usually stop once the cancer is treated. The earlier you seek treatment, the better your chances may be for remission. It’s important not to put off seeing your doctor.

Keep reading: Low T, high temps: Testosterone and night sweats »

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