Skin signs of thyroid disease

Hypothyroidism

Whatever its cause— iodine deficiency, autoimmune disease, treatment of hyperthyroidism or medications—the skin signs of inadequate thyroid hormone are similar.

The signs are rather non-specific, often subtle, and easily confused with other conditions or normality. In advanced hypothyroidism, the following symptoms may lead to a visit to the doctor and thyroid hormone testing.

  • Intolerance of cold conditions – needing to wear more clothing than previously
  • Dry skin
  • Dry, brittle, thinning hair
  • Dry, brittle, ridged or split nails

Dry Skin

Hypothyroidism Dry Skin

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Skin examination may reveal:

  • Cool, dry or waxy skin
  • Facial puffiness, especially eyelids
  • Thickened skin of lower legs with a pale or yellowish appearance
  • Thinned scalp, eyebrow, armpit and pubic hair that is coarse and dry
  • Dry, ridged or split nails

Skin swelling is myxoedema, due to the deposition of sugars called glucosaminoglycans.

Vitiligo

Skin signs of thyroid disease - Vitiligo

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The thyroid autoimmune condition Hashimoto’s thyroiditis is associated with other autoimmune diseases, including vitiligo (white patches of skin) and alopecia areata (hair loss in which there are round bald patches).

Alopecia Areata

Skin signs of thyroid disease - alopecia areata

With thyroid hormone replacement, the symptoms and signs of hypothyroidism gradually return to normal. Some patients may continue to have mildly dry skin even when blood tests indicate their thyroid hormone levels are optimal.

Thyroid hormone replacement should be undertaken gradually to avoid complications of treatment such as excessive flushing, sweating, and paradoxically, further hair loss. Hypersensitivity reactions are rare, but can include rash.

Hyperthyroidism

Excessive thyroid hormone leads to an increase in basal metabolic rate—body functions go faster than normal. For the skin, this often leads to:

  • Intolerance of hot conditions – needing to wear less clothing than previously
  • Increased perspiration and warm, moist skin, which can lead to sweat rashes in skin folds
  • Increased hair shedding
  • Rapidly growing nails that may lift off the nail bed (this is called onycholysis)

Graves’ disease is an autoaimmune disease often recognized by protruding eyes. About 2% of patients with Graves’ disease develop pretibial myxoedema. This often arises at sites of previous injury. It occurs more often in females than in males, and more often in patients over the age of 50 years than in younger people.

Signs of pretibial myxoedema are:

  • Red or brownish, thickened plaques with non-pitting oedema
  • Prominent hair follicles “like the skin of an orange”
  • Warty surface, increased hair and increased sweating
  • Distribution is usually on the shins, but sides and back of lower legs, thighs, arms and other sites may be involved

Pretibial myxoedema

Hyperthyroidism Pretibial Myxoedema

Copyright Waikato DHB and DermNet NZ (with permission)

Pretibial myxoedema can be itchy or painful and can persist after successful return of thyroid hormone status to normal levels.

As with Hashimoto’s thyroiditis, Graves’ disease is associated with other autoimmune diseases, including vitiligo (white patches of skin) and alopecia areata (hair loss in which there are round bald patches).

Skin signs of thyroid disease

Treatment of hyperthyroidism is often with carbimazole or propylthiouracil. These occasionally cause an itchy rash, which is usually mild. Rarely, hypersensitivity vasculitis arises, which can present with purple non-blanching bumps (palpable purpura) on the lower legs and feet. Palpable purpura should be urgently investigated and the drug should be stopped.