Explanation

Leukaemia means cancer of the blood. It's a problem with how white blood cell are made. They don't grow properly and don't do their job of defending your body against germs!

As well as not growing properly, these white blood cells also grow very quickly in your bone marrow, then they spill out and crowd your bloodstream. Soon there isn't enough room for your other blood cells to grow, so then they don't work properly either. This causes all kinds of problems, like neutropenia, anaemia and thrombocytopenia. Or you could have all of these things together - this is called pancytopenia.

There are several different types of leukaemia. Some are acute and some are chronic, and some affect adults more than kids. The different types are:

Acute myeloid leukaemia (AML)

Acute lymphocytic leukaemia (ALL)

Chronic myeloid leukaemia (CML)

Chronic lymphocytic leukaemia (CLL)

Hairy cell leukaemia (HCL)

Acute myeloid leukaemia

In Acute myeloid leukaemia (AML), myelocytes don't grow properly in your bone marrow. They stay immature and faulty and are called blasts. AML is an acute type of leukaemia and gets worse very quickly if it is not treated. It is rare and most often occurs in people over 40 years old.

Acute lymphocytic leukaemia

In Acute lymphocytic leukaemia (ALL), the lymphocytes don't grow properly in your bone marrow. They remain immature and faulty and are called lymphoblasts. ALL is an acute type of leukaemia and gets worse very quickly without treatment. It is the most common form of leukaemia to affect children, but no one knows what causes it.

Chronic myeloid leukaemia

Chronic myeloid leukaemia (CML) is caused by a change in a chromosome in stem cells of your bone marrow, which makes them faulty. The cells that grow from these faulty stem cells become nearly normal white blood cells - mainly granulocytes. CML develops very slowly, over months or years. It is one of the rarest types of leukaemia and it occurs mainly in adults.

Chronic lymphocytic leukaemia

In chronic lymphocytic leukaemia (CLL), lymphocytes don't grow properly in your bone marrow and also live too long! Instead of growing out of control, like in acute types of leukaemia, in CLL the faulty cells grow at a normal rate, but live longer than cells should do, so they build up this way! CLL develops very slowly, over months or years. It's the most common type of leukaemia, but it's usually people who are over 60 years old who get it.

Hairy cell leukaemia

Hairy cell leukaemia (HCL) is very rare. It gets its name because the cells that don't grow properly can look 'hairy' under a microscope, due to fine strands coming from their surfaces! It affects men five times more often than women, and the average age of people who get it is 55.