[Psoriasis and systemic lupus erythematosus: a rare association with specific therapeutic problems].

The association psoriasis and systemic lupus erythematosus (SLE) is a very uncommon association. We report three cases, diagnosed in an Internal Medicine department between 1993 and 2000. Few cases of psoriasis/SLE have been published in the literature. Psoriasis generally precedes the diagnosis of SLE. Psoriasis can also be associated with discoid lupus erythematosus. In some cases, SLE appears as a complication of ultraviolet phototherapy indicated for the psoriasis. The association psoriasis/SLE does not seem to have distinctive immunologic features. Specific therapeutic difficulties may occur. Indeed, hydroxychloroquine may exacerbate the psoriasis. Systemic use of corticosteroids raises the risk of severe psoriasis relapse during withdrawal. In addition, the diagnosis of psoriasic arthropathy is more difficult in this setting. The psoriasis/SLE association might be a good indication for using methotrexate.