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December 12, 2025The thyroid produces hormones that regulate basic body functions such as breathing, digestion, body temperature, and heart rate. However, they also support the skin’s function, which is why the skin is often the first part of the body where a disruption in hormone levels becomes noticeable.
The thyroid is a butterfly-shaped gland located in the neck. Both overactive and underactive thyroid conditions are fairly common. It is estimated that among people over 12 years old, 1 in 100 has hyperthyroidism, and 5 in 100 have hypothyroidism.
“Dermatological manifestations of thyroid dysfunction depend on the type of thyroid disorder,” says dermatologist and venereologist Dr. Markos Michelakis from EDOEAP. “In broad terms, they can be divided into three categories: a) those caused by the direct effect of thyroid hormones on the skin and its appendages (hair, nails), b) those caused by hormone effects on non-skin tissues (e.g., nerves), and c) autoimmune skin manifestations related to autoimmune thyroid diseases.”
The most common skin signs of hyperthyroidism include warm, moist, and soft skin (like a baby’s). According to earlier studies, 85% of patients with the condition exhibit this symptom. Increased warmth occurs due to higher blood flow to the skin and peripheral vasodilation, which also causes redness in areas like the face, elbows, and palms.
Hyperthyroidism can cause other symptoms as well. Hair, for example, becomes thin and soft, sometimes with diffuse hair loss (alopecia) or even premature graying. Patients may also experience excessive sweating (hyperhidrosis), generalized or localized hyperpigmentation (darkening of the skin, e.g., in skin folds or on the fingers), or white nail discoloration indicative of onycholysis (nails detaching from the nail bed).
Other hyperthyroidism-related skin manifestations include telangiectasia (visible fine blood vessels on the face, neck, or chest, forming spiderweb-like patterns) and red-brown nodules that are tender to the touch, typically appearing on the shins, calves, and feet.
Specifically, patients with hyperthyroidism due to Graves’ disease may develop pretibial myxedema, characterized by thickening and redness of the skin on the shins, sometimes with discomfort. Less than 5% of patients develop this within two years of diagnosis.
In contrast, hypothyroidism causes changes such as thickened, rough skin, hyperkeratosis, diffuse hair loss on the scalp, and nail atrophy. The skin becomes cold, pale, wrinkled, and very dry.
Indeed, rough, hard, and dry skin is the most common skin manifestation of hypothyroidism. Studies show that most patients exhibit this (e.g., over 70% of patients with Hashimoto’s thyroiditis, the most common cause of hypothyroidism).
Severe dryness is often due to reduced or absent sweating. In some cases, this leads to thickened skin on the palms and soles (keratoderma) or a network of fine cracks in the epidermis resembling shattered glass (craquelé eczema). More than half of patients also experience dryness in mucous membranes (e.g., mouth or eyes).
Other hypothyroidism-related skin signs include yellow discoloration of the palms and soles (carotenemia), cold extremities (due to constricted blood vessels), and thinning of the outer edges of the eyebrows.
Hair and nails are also affected. Hair grows slowly, becomes brittle and coarse, and may fall out. Hair growth on the rest of the body often decreases as well. Nails grow slowly and become thin, rough, and fragile.
Hypothyroidism may also slow wound healing and cause myxedema, i.e., localized swelling from the accumulation of substances around hair follicles and blood vessels.
“By ‘myxedema,’ we also refer to severe hypothyroidism that can lead to coma and be life-threatening, but this is different from the dermatological manifestations of the disease,” explains Dr. Michelakis.
He concludes: “These are only some of the skin manifestations caused by thyroid disorders. Other signs may include facial swelling (mainly around the eyes, lips, and tongue), enlargement of the nose, neck swelling, protruding eyes (exophthalmos), rashes (mainly in skin folds), transient redness that comes and goes, itching without apparent cause, etc. Anyone experiencing such symptoms should consult their doctor. It does not necessarily mean they have a thyroid disorder, but if they do, it is important to diagnose it early.”
