Signs and symptoms of leukaemia

Symptoms can depend on how quickly a leukaemia (also spelt leukemia) develops. You should see your GP if you notice any of these leukaemia symptoms.

About leukaemia symptoms

Leukaemia (sometimes spelt as leukemia) is a cancer of the blood cells. If you have leukaemia, your body makes some abnormal blood cells. These leukaemia cells behave differently from healthy blood cells.

Symptoms can depend on how quickly a leukaemia develops.

Slower growing leukaemias such as chronic lymphocytic leukaemia (CLL) and chronic myeloid leukaemia (CML) may cause no symptoms in the early stages. They may be discovered by chance after a routine blood test. If you do have symptoms, these may be mild and develop gradually. The symptoms can be confused with the symptoms of more common illnesses, such as flu.

Faster growing leukaemias such as acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL) are more likely to cause symptoms that appear over a few weeks. People often feel ill quite quickly. Most symptoms of acute leukaemia are caused by leukaemia cells filling the bone marrow. This means healthy blood cells do not move into the blood as normal.

If you have any of the following symptoms, you should always tell your doctor and have them checked. But remember, these symptoms can also be caused by many other illnesses.

We understand that showing any symptoms of what could be cancer is worrying. The most important thing is to speak to your GP as soon as possible. We're also here if you need someone to talk to. You can:

Low numbers of red blood cells

Leukaemia can stop your body making red blood cells normally. A low number of red blood cells is called anaemia. If you have anaemia, you might: 

  • look pale
  • feel very tired – this is a very common symptom
  • feel short of breath
  • feel dizzy or lightheaded
  • have palpitations (feel your heart is beating quickly).

Low numbers of white blood cells

Leukaemia can stop your body making white blood cells normally. If you have too few healthy white blood cells, you might:

  • keep getting infections
  • feel unwell and run down
  • have a sore throat or mouth
  • have a fever or high temperature.

Low numbers of platelets

Leukaemia can stop your body making platelet cells normally. This can cause unusual bleeding, such as:

  • bruising without any obvious cause
  • bleeding gums
  • nosebleeds
  • blood spots or rashes on the skin (called petechiae)
  • heavy periods.

Other symptoms

Other leukaemia symptoms may include:

  • having a fever and night sweats
  • unexplained weight loss
  • swollen lymph nodes 
  • a tender lump in the upper left-hand side of the tummy (abdomen). This is caused by an enlarged spleen
  • aching joints and bones
  • visual disturbances and headaches.


Useful words to know

When you are dealing with leukaemia, you may come across lots of new words and not know what they mean.

Some of these words are explained here. If you need more information or support, you can call the Macmillan Support Line free on 0808 808 00 00.


Something which develops and progresses quickly.


Something which develops slowly.

Lymph nodes

Small bean-shaped structures that are part of the immune system, which helps the body fight infection and disease. Lymph nodes are sometimes called lymph glands. They are connected by lymph vessels.


A type of white blood cell which fights and prevents infection.


A type of stem cell that makes red blood cells, platelets and some types of white blood cell.

Night sweats

When a person sweats a lot at night, enough to soak through bedclothes and bedding.


Changes in the body that suggest a person may be unwell or have an illness.

About our information

  • References

    Below is a sample of the sources used in our leukaemia (leukemia) information. If you would like more information about the sources we use, please contact us at

    Phelan K and Advani A. Novel therapies in acute lymphoblastic leukemia. Current Hematologic Malignancy Reports. 2018.

    Heuser M et al. Acute myeloid leukaemia in adult patients: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Annals of Oncology, 2020, vol 3, issue 6. Available from [accessed 2021].

    Hochhaus A, Saussele S, Rosti G, et al. Chronic Myeloid Leukaemia: ESMO Clinical Practice Guidelines. Annals of Oncology, 2017; 28 (suppl 4), iv41-iv51. Available from [accessed on October 2020].

    Eichhorst B et al. Chronic lymphocytic leukaemia: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. ESMO Guidelines Committee. October 2020.

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Anne Parker, Consultant Haematologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 March 2022
Next review: 01 March 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.