The cause of discoid lupus erythematosus (DLE) is not fully understood. It has been suggested that it is an autoimmune condition (body attacks itself). It is diagnosed by skin biopsy and blood tests to exclude other forms of lupus. Good basic explaination can be found here : http://www.aocd.org/skin/dermatologic_diseases/discoid_lupus_eryt.html http://www.bad.org.uk/public/leaflets/discoid.asp Your GP will be able to inform you, your specialist will have access to a wide variety of information and support. Your local medical library may be able to assist.