A fluid swelling that’s chronic, persisting for months, in any part of the body is likely to be a lymphoedema. Although thought to be relatively uncommon it is estimated that at least 100,000 people in the UK have lymphoedema. It occurs when the lymphatic system, which is responsible for draining waste materials away from the tissues, stops working properly. When the lymphatic system is damaged, fluids accumulate in the tissues, causing swelling. If left untreated, the swelling can become hard and extremely painful. It can affect any part of the body but most commonly occurs on the limbs. Lymphoedema can be a distressing side effect of surgery for cancer, of the breast or prostate for example, when lymph nodes are removed. Likewise, radiotherapy can cause scar tissue which can damage the lymphatic system. However, three-quarters of lymphoedemas occur in patients that have not had cancer. Injury, reduced mobility and problems with the veins can all increase your risk of developing it. Because the lymphatic system is not well understood, lymphoedema has been misdiagnosed as a sprained ankle, water retention or swelling from an allergic reaction. While lymphodema is not curable, there's a great deal that can be done to help, particularly if the condition is caught early. Skin care, compression stockings, exercise and massage can all help to reduce moderate swelling. But treatment needs to be tailored to the individual. Severe swellings need a more intensive treatment programme. Compression and massage can help, but how effective is drug therapy or surgery? Barbara Myers puts listeners' questions about lymphoedema and how to manage it to Peter Mortimer, Professor of Dermatological Medicine to the University of London at St George’s and the Royal Marsden Hospitals, London.