Hydroxychloroquine is used to prevent and treat acute attacks of malaria. It is also used to treat discoid lupus erythematosus (DLE; a chronic inflammatory condition of the skin) or systemic lupus erythematosus (SLE; a chronic inflammatory condition of the body) and rheumatoid arthritis in patients whose symptoms have not improved with other treatments. Hydroxychloroquine is in a class of drugs called antimalarials.