BACKGROUND: Leprosy (Hansen's disease) is a curable, chronic contact infectious disease caused by Mycobacterium leprae. It mainly affects human skin and nerves and can cause progressive and permanent damage to the skin, nerves, limbs, eyes and is of great concern to the medical community. CASE PRESENTATION: A 35-year-old Han Chinese female patient presented to our hospital with 11 years of recurrent erythema and pain in the limbs and face, which was aggravated by fever for 6 days. The patient had an 11-year history of systemic lupus erythematosus (SLE). Initially, lupus was considered to be active and was subsequently treated with methylprednisolone
however, the rash was not controlled. By completing pathohistological examination, immunohistochemistry, and antacid staining, according to the Ridley-Jopling classification of leprosy, confirmed a diagnosis of lepromatous leprosy. CONCLUSIONS: This report will help increase awareness of leprosy in patients with immune disorders to reduce the rate of misdiagnosis and mistreatment.