In Hashimoto's disease, various changes occur in the body's functioning, particularly related to hormonal imbalances. One significant aspect affected is the skin, which experiences disrupted blood supply. Patients often have skin that feels cool to the touch, as well as dry and rough in texture.
Thyroxine (the T4 hormone produced by the thyroid gland) plays a crucial role in the proper functioning of the sebaceous glands. A deficiency in this hormone leads to flakiness and dryness of the skin. As a result, the epidermis tends to flake and undergo keratinization due to increased production of keratin and intercellular lipids, which contribute to transepidermal water loss. Keratinization is particularly noticeable on the feet, elbows, and knees. On the feet, this keratinization often occurs in areas that experience the most pressure, such as the heels, leading to brittle and cracked heels accompanied by flaking skin.
In addition to paleness, the skin may exhibit a yellow tint due to impaired metabolism of carotene by the liver. When carotene is not properly metabolized, it can accumulate in the stratum corneum of the epidermis. This excess carotene is then excreted through sweat and can be reabsorbed by the skin, often depositing in areas where sebaceous glands are present. Furthermore, when the temperature drops in the environment, bluish-red streaks may appear on the skin. These streaks are characterized by a reticular pattern that resembles marble. This symptom, associated with hypothyroidism, is skin marbling.
