Pretibial myxedema is seen in: March 2005

Ans. C: Liyrotoxicosis P-etibial myxedema/ thyroid dermopathy/ localized myxedema, nearly always occurs in patients who have severe Graves' ophthalmopathy. Pretibial myxedema is thought to be caused by the activation of dermal fibroblasts, the basic cell precursors that make up skin cells and by the stimulation of connective tissue cells by TSH receptor antibodies. In PTM, activated fibroblasts tend to produce excess deposits of hyaluronic acid, and it is this imbalance in glycosaminoglycan proteins that leads to dermal changes.