Western Blotting as the Confirmatory Test for Syphilis in a Patient With Systemic Lupus Erythematosus

We describe a patient with systemic lupus erythematosus (SLE) who developed a palmoplantar eruption and positive serologic findings consistent with secondary syphilis. Because of the presence of antiphospholipid antibodies, patients with SLE can have both false-positive nontreponemal and treponemal-specific tests. Western blotting was used to confirm a positive diagnosis of syphilis in our patient. Western blotting is one of the most specific tests in determining whether a patient with SLE has syphilis.¹ This case demonstrates the utility of the Western blot with respect to diagnosing syphilis in patients with autoimmune disease.