[Graves' dermopathy on the big toe].

Localized myxoedema is a rare dermopathy in patients with Graves' disease. The pretibial area is the most commonly affected region but herein we present a case of myxoedema of the big toe. A 44-year-old male with Graves' disease ongoing for seven years presented bilateral ophthalmopathy and myxoedema of the big toes. The myxoedema was treated successfully with intralesional steroids. The physiopathology of myxoedema involves fibroblast activation and glycosaminoglycan production. This activation could result from stimulation of TSH receptors at their surface by TSH receptor antibodies (TRAK) or from an inflammatory process. The pretibial topography may be related to the high frequency in this area of microtrauma, with modulation of the cytokine microenvironment. The atypical localization seems to correlate with a Koebner phenomenon. Treatment of Graves' disease is generally insufficient to resolve the cutaneous problems. Topical corticosteroid therapy generally results in rapid improvement of recent lesions.