Hairy cell leukaemia is one of the rarest types of leukaemia, which is cancer of the white blood cells.

It gets its name from the fine, hair-like strands around the outside of the cancerous cells, which are visible under a microscope.

It’s not known what causes hairy cell leukaemia. The condition most commonly affects people aged 40-60 and is more common in men than women.

Symptoms of hairy cell leukaemia

The symptoms of hairy cell leukaemia develop slowly and are similar to those of other types of leukaemia. They include:

  • unintentional weight loss 
  • pale skin
  • weakness, tiredness and breathlessness
  • frequent infections
  • bleeding or bruising easily
  • pain or swelling in your abdomen (tummy) (see below)

The abnormal white blood cells can accumulate in your spleen, causing it to increase in size. The spleen is an organ in the upper left side of your abdomen, behind your stomach and ribs.

If your spleen is enlarged, it’s likely you’ll have a painful lump on the left side of your abdomen. If this is the case, you should visit your GP so the lump can be examined.

An enlarged spleen may remove normal blood cells from your bloodstream. This can lead to a further reduction in the number of normal red and white blood cells and platelets in your blood.

Diagnosing hairy cell leukaemia

If your GP suspects leukaemia, they may refer you to a haematologist (a specialist in blood disorders).

The haematologist will carry out blood tests to determine how many different types of blood cells there are in your blood sample. This is known as a full blood count (FBC).

If you have hairy cell leukaemia, it’s likely your red blood cell and platelet counts will be low.

A bone marrow sample may also be taken, which gives the haematologist more detailed information about your condition.

An ultrasound scan or a computerised tomography (CT) scan may be needed to examine your spleen.

Treatment for hairy cell leukaemia

As hairy cell leukaemia develops slowly, immediate treatment may not be needed. You’ll have regular blood tests to monitor your condition.

Treatment may be recommended if the number of abnormal white blood cells increases or if you develop symptoms.

Chemotherapy is the main treatment for hairy cell leukaemia and is usually effective at destroying the cancerous cells. The two main chemotherapy medications used are:

  • cladribine – given as either an injection just under the skin, or through a drip directly into a vein (infusion)
  • pentostatin – given as an injection directly into a vein (intravenously) every two weeks

Rituximab, a type of medication known as a monoclonal antibody, may sometimes be used in combination with chemotherapy. It works by attaching to a protein found on leukaemia cells and the immune system then targets and kills the cells.

Surgery to remove the spleen is rarely used as a treatment for hairy cell leukaemia. However, removal of your spleen may be recommended if:

  • it’s enlarged and is causing pain or discomfort
  • it’s destroying large numbers of red blood cells or platelets
  • it hasn’t reduced in size after chemotherapy

As with most types of cancer, the outlook for hairy cell leukaemia will depend on how far the condition has advanced at the time of diagnosis and how well it responds to treatment.

As hairy cell leukaemia is a rare type of cancer, it’s difficult to accurately predict how it will affect individuals in the long term.

The Cancer Research UK website has more information about:

Types of treatment for hairy cell leukaemia

Staging hairy cell leukaemia

Living with hairy cell leukaemia