About leukaemia symptoms

Symptoms can depend on how quickly a leukaemia (also spelt leukemia) 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.

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
  • feel short of breath
  • feel dizzy or lightheaded.

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 in women.

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.

About our information


  • 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 Editors, Dr Anne Parker, Consultant Haematologist; and Dr Helen Marr, 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.