[Graves disease. An important differential diagnostic consideration for systemic lupus erythematosus]

Graves disease is a frequent cause (30-40%) of hyperthyroidism. In addition to the classic clinical triad (goiter, exophthalmos and tachycardia), symptoms relating to other organ systems may be found at presentation. Cutaneous manifestations play an important role and may initially be the only clue to the endocrine disorder. A 40-year-old woman with Graves disease presented with features of systemic lupus erythematosus. She had a malar rash, as well as marked hematological changes (thrombocytopenia and leukocytopenia) and antinuclear antibodies (1:640). She also had hyperthyroidism and Graves disease-specific thyroid autoantibodies (TSIg). Her symptoms improved after initiation of antithyroid therapy. Because of overlapping clinical and laboratory criteria, Graves disease can mimic systemic lupus erythematosus. The differentiation requires careful laboratory evaluation. Moreover, both autoimmune diseases may occur in the same patient.