A 30-Year-Old Woman with a History of Autoimmune Hyperthyroidism Presenting with Fever and Oral Ulcers, Diagnosed with Discoid Lupus Erythematosus.

BACKGROUND Lupus erythematosus (LE) is mainly clinically divided into cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) depending on the presence of multi-system manifestations. The most common subtype of CLE is discoid lupus erythematosus (DLE). Graves' disease (GD) is immunologically characterized by lymphocytic infiltration of the thyroid gland and the presence of thyroid-stimulating hormone (TSH) receptor antibodies (TSH-R-Ab), and is the most common autoimmune pathogenic cause of hyperthyroidism. Autoimmune thyroid dysfunction has been widely described in association with rheumatic diseases. A certain rate of coexistence of GD with LE, mainly SLE, has been reported in the literature. Herein, we present a rare case of Graves' hyperthyroidism complicated with DLE. CASE REPORT A 30-year-old female patient, with a history of hyperthyroidism and discontinued methimazole treatment, initially presented with symptoms of infection and oral ulcers. Thyroid hormone, thyroid-stimulating hormone receptor antibody, and immunological tests were consistent with a diagnosis of Graves' hyperthyroidism-associated DLE. Corticosteroids and radioactive iodine (RAI) were used to treat DLE and GD, respectively. Post-treatment evaluation suggested the remission of her hyperthyroidism and active DLE. CONCLUSIONS Autoimmune thyroid diseases have been previously described in association with rheumatic diseases. This association shows the importance of prompt awareness of the increased risk of DLE when evaluating autoimmune thyroid dysfunction, especially under certain conditions, such as after treatment with anti-thyroid drugs (ATDs), or in the absence of multiple organ damage manifestations of SLE.