Systemic lupus erythematosus (SLE) is a systemic autoimmune connective tissue disease more precisely a type III hypersensitivity reaction that can affect any part of the body. SLE is a disease of remissions and flares; a clinical activity index would enable standardisation of definition of flare and measurement of reduction in disease activity in response to treatment. Such scales could then be used to dictate the need for or response to treatment in clinical trials or to monitor the course of disease in longitudinal studies of outcome.