There are two types of lupus.
Discoid lupus is a characteristic rash without significant problems.
SLE is an inflammatory disease whereby various target tissues in the body become inflamed and produce symptoms due to this process. The inflammation can also change the function of some of the inflamed tissue and if it persists may lead to long term damage in such structure. Inflammation in a joint may cause arthritic symptoms, in the skin a rash, or in the kidneys may result in nephritis. Sometimes the lupus process will also affect the blood cells of the body causing a low blood count. Many features of these diseases are shared and overlaps between them do occur.