Hodgkin lymphoma is caused by a change (mutation) in the DNA of a type of white blood cell called B lymphocytes, although the exact reason why this happens isn't known.
The DNA gives the cells a basic set of instructions, such as when to grow and reproduce. The mutation in the DNA changes these instructions so the cells keep growing, causing them to multiply uncontrollably.
The abnormal lymphocytes usually begin to multiply in one or more lymph nodes in a particular area of the body, such as your neck or groin. Over time, it's possible for the abnormal lymphocytes to spread into other parts of your body, such as your:
While the cause of the initial mutation that triggers Hodgkin lymphoma is unknown, a number of factors can increase your risk of developing the condition. These include:
Hodgkin lymphoma isn't infectious and isn't thought to run in families. Although your risk is increased if a first-degree relative (parent, sibling or child) has had lymphoma, it's not clear if this is because of an inherited genetic fault or lifestyle factors.
Hodgkin lymphoma can occur at any age, although most cases are diagnosed in people in their early 20s or 70s. The condition is slightly more common in men than women.