Lupus: an immune system disorderSOME 50,000 may have lupus in the UK; 90 per cent of sufferers are female, mainly between the ages of 15 and 55. Lupus is a chronic (long-lasting) autoimmune disease in which the immune system, for unknown reasons, becomes hyperactive and attacks normal tissue. This attack results in inflammation and brings about symptoms. Worldwide, lupus is more prevalent than leukaemia, muscular dystrophy and multiple sclerosis. It can sometimes mimic the symptoms of MS. Lupus is difficult to diagnose because its symptoms are so varied and can appear like other diseases. The condition can be overlooked, sometimes for years, unless the GP or consultant is alert to the possibility of lupus. It can be mild, disabling or can even be fatal. There are two main forms of lupus. One, discoid lupus, affects only the skin, whereas the other, systemic lupus, involves the joints and may involve the internal organs as well. Joint and muscle aches and pains and extreme fatigue and weakness are the two most common groups of symptoms. The most prevalent skin problem in lupus is the butterfly rash. This is a red rash, sometimes no more than a mild blush, that occurs across the bridge of the nose and on the cheeks resulting in a distinctive butterfly-like appearance. As a result the butterfly (pictured) has become a symbol of lupus charities world-wide. The exact cause is unknown, but it is likely to be a combination of factors. A person's genetic make-up and exposure to certain trigger factors may provide the right environment in which lupus can develop. The term "lupus" was derived from the Latin word for wolf. The majority of people living with lupus today can expect to live a normal life span. About 20 or so years ago it was a different matter, many more people died from lupus. This was due to the fact that it was only diagnosed when it was very severe and treatments weren't as effective. There are many possible manifestations of lupus. Below are some of the most common. A lupus sufferer may have four or five symptoms; permanent rash over cheeks; extreme fatigue and weakness; kidney problems; rashes from sunlight/UV light; poor blood circulation; depression; hair loss; miscarriages and haematology disorders including anaemia