Acute lymphoblastic leukaemia (ALL) It comes as a shock to hear a diagnosis of acute lymphoblastic leukaemia (ALL), especially if everything is happening fast. Because ALL is a blood cancer that can get worse quickly, most people start treatment immediately. About half of ALL diagnoses are in children, making it a very worrying and difficult time for parents and families. Diagnosis and treatment are complex, so we have some clear information to help you understand the basics of ALL. The name tells you a couple of things about ALL. 'Acute' means the leukaemia develops rapidly, and 'lymphoblastic' means it affects a particular group of white blood cells. ALL happens when your body makes too many immature white blood cells. These leukaemia cells can crowd out the red blood cells and platelets in your bone marrow, which is the body’s 'factory' where your blood cells are made. The leukaemia cells may also spread to other parts of the body, including the brain. In our general information about leukaemia, you can learn more about blood cells, and the way they are made in a process called haematopoiesis. What are the symptoms of ALL? The symptoms of ALL start slowly at first, but then suddenly become severe. These symptoms can include: tiredness pale skin feeling breathless getting lots of infections unusual bleeding or bruises fever bone and joint pain pain in your abdomen swollen glands in your neck, armpits, or groin weight loss a purple rash If the brain is affected, there can also be headaches, blurred vision, dizziness, seizures (fits) or vomiting. What causes ALL? We don't know what causes ALL. The chances of developing ALL are higher than usual for people who: Have certain inherited conditions, including Down's syndrome Have weakened immunity, for example from HIV or AIDS, or drugs that suppress the immune system Had previous chemotherapy Smoke Are overweight ALL is rare, but it happens most often in young children. The chances of developing ALL go down in middle age, and then start rising again in older people. It happens more often in males than in females. How is ALL diagnosed? If ALL is suspected, you'll be offered blood tests and a bone marrow biopsy to confirm the diagnosis. In the lab, the cancer cells are analysed to identify abnormal genes and find out what type of ALL you have. The result is important because it helps your doctor recommend the best treatment. Some people with ALL have what’s called 'the Philadelphia chromosome' in their cancer cells. Your doctor may also recommend having a: chest X-ray lumbar puncture brain scan (CT or MRI) What are the types of ALL? Overall, there are three main types of ALL, based on which kind of white blood cell is affected: B-cell lymphoblastic leukaemia (plus the sub-type, see below) B-cell lymphoblastic leukaemia, not otherwise specified T-cell lymphoblastic leukaemia Within these categories, there are different sub-types. These depend on the kind of cancer gene that's found in the leukaemia cells, to identify the sub-type.