Increased risk of infection

White blood cells help your body fight infection. They are made in your bone marrow. Some cancers and cancer treatments can lower the number of white blood cells in your blood. This is called neutropenia.

When your white blood cell count is low, it’s harder for your body to fight infections. Even a minor infection such as a sore throat or a cold can become more serious.

White blood cells may be low because of:

• Cancers that affect the blood or bone marrow
• Chemotherapy
• Some targeted therapies
• Some immunotherapy treatments
• Other cancer medicines

White blood cell levels often reach their lowest point around 7 to 14 days after treatment, although this varies depending on the treatment you are receiving.

Symptoms of an infection include:

• A high temperature of 37.5 degrees Celsius and above 
• A low temperature of 36.0 degrees Celsius and below 
• Feeling shivery, cold or feverish
• Flu-like symptoms
• Muscle aches or joint pains
• Feeling generally unwell
• Headache
• A new or worsening cough
• Green or yellow phlegm
• Shortness of breath
• Sore throat
• Mouth soreness or ulcers
• Toothache
• Vomiting
• Diarrhoea
• Needing to pass urine more often than usual
• Pain or discomfort when passing urine
• Redness, pain or swelling around a PICC line, PORT or central line
• Red, swollen, hot or painful skin
• Feeling unusually weak, dizzy, faint or fatigued

Contact your hospital team, treatment centre or emergency number immediately if you have any symptoms of infection.

You may need urgent assessment, even if it is overnight or at the weekend. Do not delay in contacting the hospital. 

Checking your temperature

Ask your nurse how to take your temperature correctly, and what to do if you feel unwell.

You may be advised not to take paracetamol or ibuprofen without first speaking to your hospital team, as these medicines can mask a fever.

Always follow the advice given by your hospital team.

If an infection is suspected, you may need:

• Blood tests
• Other tests to identify the cause of infection. For example, a chest x-ray or a urine sample
• Antibiotics
• Antiviral medicines
• Admission to hospital for monitoring and treatment

Treatment should start quickly if an infection is suspected.

Antibiotics

If you develop an infection, you may need antibiotics. These may be given:

• As tablets
• Through a drip into a vein (intravenously)

If you have a higher risk of infection, you may be prescribed antibiotics to help prevent infection.

Growth factors

Some people may have to take medicines called growth factors to help the bone marrow produce white blood cells more quickly. 

These medicines are usually given as an injection under the skin. One commonly used growth factor is called G-CSF.

Your doctor will let you know if this is recommended for you. Read more about growth factors here.

Immunoglobulin treatment

Some patients who experience repeated serious infections may be offered immunoglobulin treatment. Immunoglobulins are proteins that help the immune system fight infection. They are usually given through a drip into a vein.

• Have a thermometer at home and know how to use it.
• Make sure your family members know the signs of infection and who to call if you become unwell.
• Wash your hands regularly, especially before eating and after using the toilet.
• Carry hand sanitiser when away from home.
• Keep cuts, scratches and wounds clean and dry.
• Wear gloves for gardening, cleaning or activities where you might injure your skin.
• Avoid close contact with people who have contagious illnesses such as flu, COVID-19, chickenpox, shingles or measles.
• Drink plenty of fluids unless advised otherwise by your healthcare team.
• Use a soft toothbrush.
• Brush your teeth regularly.
• Use mouthwashes recommended by your healthcare team.
• Attend routine dental check-ups when advised.
• Speak to your cancer team before having dental treatment.

Food safety

Good food hygiene is important:

• Wash fruit and vegetables thoroughly.
• Avoid raw or undercooked meat, poultry, seafood and eggs.
• Avoid unpasteurised dairy products.
• Store food safely and follow use-by dates.

Not all cancer patients need a strict diet. Your healthcare team will tell you if any additional food restrictions apply to you.

Vaccinations

Vaccinations can help protect you from serious infections. Ask your doctor or nurse:

• Which vaccines are recommended for you
• The best time to receive them during treatment

You may be advised to have:

• An annual flu vaccine
• A COVID-19 vaccine or booster
• A pneumococcal vaccine

Some vaccines, particularly live vaccines, may not be suitable during cancer treatment or while your immune system is weakened. Always check with your cancer team before receiving any vaccination.

If your immune system is very low, you may also be given medicines to help prevent infections such as shingles.