Hyperthyroid Disorders

Lesson 8: Accompanying Conditions and Complications

Dermopathy--Skin Conditions in Hyperthyroidism

Dermopathy refers to the skin changes that can accompany thyroid disorders. The three disorders described here, pretibial myxedema, acropachy, and vitiligo are all related to autoimmune thyroid disease. They are primarily seen in Graves’ disease or autoimmune hypothyroidisms. Although thyroiditis responsible for hyperthyroidism is autoimmune in nature, it generally is of short duration, not long enough for dermopathy to develop.

Pretibial myxedema
Pretibial myxedema or PTM, like TED, is caused by deposits of the immune system chemical GAG and white blood cells, and it is associated with high levels of TSH receptor antibodies. For this reason, it is most likely to occur after radioiodine ablation treatment for hyperthyroidism and it is almost always seen in patients with severe TED. PTM occurs in 2-3 percent of patients with Graves’ disease. Rarely, it occurs in patients with Hashimoto’s thyroiditis.

PTM causes a type of myxedema, which is a condition of edema or swelling, which primarily occurs in the pretibial area. The pretibial area refers to the front lower legs and shin. In severe PTM, the arms and upper back may also be involved. PTM causes characteristic waxy, brownish lesions and swelling. If the nerves are compressed or infiltrated, the skin may feel painful. Patients are usually treated with topical glucocorticosteroid creams. If pain is present, oral steroids or intravenous immunoglobulins may be used.

Acropachy
Acropachy is a condition characterized by soft tissue swelling that affects the hands and feet. Acropachy usually occurs in patients with PTM and TED, and it may develop as long as 40 years after the initial thyroid disorder. It is most likely to be seen in patients who have had radioiodine ablation.

Approximately 7 percent of patients with PTM go on to develop acropachy. Males and females are affected equally. Typically, swelling affects both hands or both feet equally and there is clubbing of the fingers and toes. Although the tissues are swollen, the joints are not affected. The skin is usually pigmented and leathery with equal involvement of lower and upper extremities. When severe acropachy causes a condition of elephantiasis, in which the hands and feet become enlarged with tapered swollen digits.

Vitiligo
Vitiligo is a pigmentation disorder in which antibodies to melanin destroy pigment in the skin, mucous membranes and retina. This causes white patches of unpigmented skin as well as the hair growing in the area. Vitiligo affects both women and men equally and seen in equal distribution in all races. Vitiligo is more common in autoimmune hypothyroidism although it occurs in approximately 7 percent of patients with Graves’ disease. Treatment includes medical, surgical and adjunctive therapies. Psoralen photochemotherapy is the most widely used treatment for vitiligo.

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