Sweating and cancer

Why do we sweat?

Sweating is how the body controls its temperature. When the temperature inside our body increases, the sweat glands release water onto the skins surface. As the water dry’s up (evaporates) it cools the skin and blood underneath it.

We have sweat glands in the skin over most parts of our body. They are in the layer of the skin called the dermis. The nerve cells in the dermis control sweating.

Although we don’t realise it, we are constantly sweating. The amount of sweat we make depends on:

• what we are doing

• our emotional state

• the temperature around our body

We sweat more when:

• it is hot

• we exercise

• we are nervous, angry or upset

• we go through the menopause

• we are ill

• we take medicines that cause sweating

Causes of sweating

When you have cancer things that may increase sweating include:

Infection

Infection is a common cause of sweating in people with cancer. Infection can give you a high temperature, and your body sweats to try and reduce it. Treating the infection can control or stop sweating.

The cancer itself

Some cancers can cause you to sweat more than usual. These include:

• non-Hodgkin lymphoma

• Hodgkin lymphoma

• leukaemia

• mesothelioma

• bone cancer

• prostate cancer

• kidney cancer

• germ cell tumours

• advanced medullary thyroid cancer

Some neuroendocrine tumours can also cause sweating as a symptom. Some of these include insulinoma and phaeochromocytoma (pronounced fey-oh-cromo-sy-toma).

People with advanced cancer of any type may also have increased sweating.

Find information about your cancer type

Hormone changes

Changes in hormone levels can cause hot flushes and sweats. Your hormone levels may change because of the cancer itself or because of treatment. This includes treatments such as:

• surgery

• chemotherapy

• radiotherapy

• hormone therapy

• immunotherapy

• targeted cancer drugs

Treatment for breast cancer can put women into an early menopause. For some women, this causes hot flushes and sweats. Women who have already had their menopause can have hot flushes again when they start hormone treatment.

Men can have hot flushes and sweating when they have hormone treatment for prostate cancer or breast cancer.

Read more about sex hormone symptoms and cancer

Medicines and cancer drugs

Sweating and hot flushes can be a side effect of some drug treatments, including chemotherapy and morphine.

Find out more about the side effects of individual cancer drugs

Treating the cause of sweating

The treatment you have to stop your sweating, depends on what is causing it. If you have an infection, antibiotics will treat the infection and stop the sweating. If your sweating is due to cancer, then treating the cancer can stop it.

If you are sweating because treatment has changed your hormone levels, it may settle down after a few weeks or months, once your body is used to the treatment.

Talk to your doctor or nurse if sweating is troubling you. There are different treatments you can try.

Medicine to treat hot flushes and sweats

Some drugs help to reduce the number of hot flushes and sweats you have and can make them less severe. They include drugs such as:

• clonidine - a blood pressure and migraine medicine. It can help women with breast cancer

• anti depressants such as paroxetine or venlafaxine

• gabapentin - this is a medicine used for people with epilepsy, but it can help women with breast cancer

• medroxyprogesterone or cyproterone acetate can help men with prostate cancer

• oxybutynin – this is a medicine to relax the muscles of the bladder and stops sudden muscle spasms. It can also help reduce sweating

All these treatments have side effects. It is important to talk to your doctor about them before you start and discuss how long you should take them. We need more research to find the best way to reduce hot flushes and sweats.

People sometimes use complementary medicines to help control sweating. Research has had varying results so far.

Read more about complementary therapy

Things you can do to reduce sweating

• Avoid alcohol and caffeine as this open ups (dilates) the blood vessels in the skin, increasing sweating.

• Avoid spicy foods and eating large meals late at night.

• Keep your room at a cool, comfortable temperature.

• Have a fan nearby at night or use a handheld fan.

• Wear layers of clothes so you can easily take off or put on a layer to adjust your temperature.

• Use light cotton bed clothes so you can remove them if you get hot.

• If you are sweating a lot at night, lie on a soft towel to soak up moisture and keep your sheets dry.

• Keep hydrated. The usual advice is to drink 6 to 8 glasses a day. For example, water, sugar free drinks and milk. If you are sweating, you need to drink much more as you can lose a lot of fluid in sweat.

• Have a lukewarm or cool shower or bath before bed.

• Use an antiperspirant instead of a deodorant. Antiperspirants help to lessen how much sweat you produce, whereas deodorants cover or neutralise the smell.

• Wear moisture wicking socks and change them at least twice a day. Moisture wicking socks soak up sweat and pull it away from the skin to help prevent blisters and smells.

Things you can do to help lessen the look of you sweating

• Wear white or black clothing as this helps reduce the signs of sweating.

• Use underarm pads that can soak up any extra sweat so it can protect your clothes.

• Wear loose fitting clothing.