Thyroid Hormone Action on Skin

The document from 2011 outlined the complex effects of thyroid hormone on skin, including direct actions on skin tissues, effects stemming from actions on non-skin tissues, and autoimmune skin diseases linked to thyroid dysfunction. It detailed how hypothyroidism can cause rough, scaly skin with myxedema due to glycosaminoglycan accumulation, and affect hair and nail growth, leading to dryness, brittleness, and alopecia. Hyperthyroidism, on the other hand, can result in smooth, thin skin with hyperhidrosis, fine hair, and nail changes. The hormone's influence extends to the regulation of epidermal keratinocytes and dermal fibroblasts growth, gene expression related to skin and hair follicle function, and sweat gland activity. The document also discussed skin manifestations of thyroid autoimmune diseases, such as vitiligo and alopecia areata, and specific conditions like Graves' disease which can cause thyroid dermopathy and acropachy. It mentioned the potential therapeutic effects of topical thyroid hormone on wound healing and hair growth, and the role of thyroid hormone analogs in skin atrophy and wound healing.