Cutaneous signs of thyroid disease.

Hyperactivity of the sympathetic nervous system produces many of the skin changes of hyperthyroidism, while the hypometabolic state and the accumulation of mucopolysaccharides in the dermis are responsible for hypothyroid cutaneous manifestations. Acropachy, atopic eczema, localized myxedema and nail changes are associated with thyrotoxicosis. Vitiligo may be seen in all three thyroid diseases of autoimmune origin. Hyperpigmentation, pruritus and urticaria are associated with hyperthyroidism.