A 38-year-old caucasian woman developed typical Graves' hyperthyroidism and ophthalmopathy while being chronically treated for pemphigus vulgaris with low doses of glucocorticoids capable of effectively controlling skin disease. HLA typing showed positivity for DR3 and DR4, suggesting a genetic susceptibility for both Graves' disease and pemphigus vulgaris. The apparent contradiction whereby thyroid autoimmune disease flared up during therapy with glucocorticoids, known for their immunosuppressive effects, may be related to the dose of steroids. It is possible that high doses of glucocorticoids, commonly employed in the treatment of severe Graves' ophthalmopathy, might indeed suppress the disease, whereas the low doses used in this patient might precipitate or aggravate it.