Dermopathy is a recognized but rare extrathyroidal manifestation of Graves’ disease (GD), affecting 1.5% of patients. The pathogenesis of this manifestation remains poorly understood but is most likely triggered by autoimmunity to the thyroid stimulating hormone (TSH) receptor and possibly the insulin like growth factor (IGF-1) receptor. We present two cases of dermopathy related to GD to highlight the challenges associated with diagnosis and management of this condition.
The first case involves a 38 year-old man, diagnosed with GD in 1997. He was treated with carbimazole, followed by radioactive iodine. He then developed significant Graves’ orbitopathy (GO) requiring decompressive surgery. Following this he developed left great toe swelling with severe skin thickening, clubbing and erythema spreading up his left shin. Despite treatment with compression bandaging, lymphoedema dedicated physiotherapy, topical and intravenous corticosteroids his dermopathy progressed and now involves both lower limbs.
The second case involves a 53 year-old man diagnosed with GD in 2010. He had gross GO with proptosis, periorbital swelling, chemosis, lid lag and ophthalmoplegia. He also had clubbing and severe bilateral skin changes with circumferential involvement of his lower limbs, plaques, verrucous change and a 3x4cm soft tissue swelling overlying the proximal phalanx of his right great toe.
He was treated with suppressive doses of carbimazole and with thyroxine replacement to maintain a euthyroid state. His GO and dermopathy have not improved despite intravenous methylprednisolone, topical steroid ointment and compressive bandaging.
Both patients have strong family history of autoimmune disease, extensive smoking history and consistently elevated TSH receptor antibodies despite treatment.
The mainstay of treatment for dermopathy is systemic glucocorticoid therapy however efficacy of this treatment is limited in severe disease. Multiple novel therapies are being investigated for GO, including rituximab, which may be applicable to treatment of dermopathy due to a likely shared pathogenesis.