Hairy cell leukaemia is a rare type of chronic leukaemia, so called because the leukaemia cells look as if there are hair-like protrusions on their surface when viewed down a microscope.

Leukaemia is a cancer of the blood. It affects the white blood cells, which are a really important part of our immune system that fights infection.

What is hairy cell leukaemia?

Hairy cell leukaemia is a type of chronic leukaemia meaning it develops slowly, often over many years. It affects a type of white blood cell called lymphocytes. It is called hairy cell leukaemia beucase the cancer cells look as if there are hair-like protrusions on their surface when viewed under a microscope.

What are the signs and symptoms?

Because hairy cell leukaemia is a chronic disease that develops gradually the symptoms are not always obvious at first. Many patients will not have any symptoms at the time they are diagnosed – usually while having a routine blood test for some other illness.

The symptoms of hairy cell leukaemia are very non-specific and can be confused with those of other common illnesses such as flu. The most common symptoms include:

• Tiredness and breathlessness
• Frequent and persistent infections
• Abdominal pain due to enlarged spleen

These symptoms are caused by a lack of healthy red and white cells and platelets in the blood. Patients may only experience some of these symptoms.

What causes it?

There is no single factor known to cause hairy cell leukaemia. In most cases it is probably due to a combination of different factors.

How common is hairy cell leukaemia?

Hairy cell leukaemia is rare and accounts for only 2% of all leukaemias.

Around 200 people are diagnosed with hairy cell leukaemia in the UK every year. Hairy cell leukaemia usually occurs in middle age. It is unknown in children and rare in teenagers. 

Hairy cell leukaemia is much more common in men than women.