Skin symptoms can be linked to thyroid disease

Camden, N.J. - Dermatologists know that skin symptoms can often be linked to the pathologies of internal organs, and the cutaneous manifestations of thyroid disease are no exception.

According to one expert, it is the task of the dermatologist to not only recognize and treat the systemic and cutaneous symptoms of thyroid disease, but also to keep an open mind in terms of the disease and syndrome associations that thyroid disease may have and address these aspects, as well.

The incidence of thyroid disease in the United States has been estimated to be 4.6 and 1.3 percent for hypothyroidism and hyperthyroidism, respectively.

Lesions

The cutaneous manifestations of thyroid disease can be seen as specific lesions such as thyroglossal duct cysts and cutaneous metastases from thyroid malignancies, they can present as non-specific signs secondary to thyroid imbalances such as hyperthyroidism (Graves’ disease) and hypothyroidism (Hashimoto’s thyroiditis), or can appear in associated dermatologic and systemic disorders such as in autoimmune diseases and more rarely in other disorders such as Cowden disease, Carney complex and McCune-Albright syndrome.

“I believe that dermatologists need to be cognizant of the many ways that the thyroid gland is associated with dermatologic disorders. It is of paramount importance that they are aware of the different thyroid diseases in order to better treat and manage their patients,” says Warren R. Heymann, M.D., professor of medicine and pediatrics and head of the division of dermatology at the University of Medicine and Dentistry of New Jersey, Camden, N.J.

Cysts

Thyroglossal duct cysts (TDC) are the most common congenital cystic abnormality of the neck, representing 70 percent of such lesions, and are just one example of thyroid disease that can present with cutaneous symptoms. Other thyroid disease pathologies include cutaneous metastases from thyroid cancer.

Clinical features can vary ranging from solitary or multiple, flesh-colored, violaceous or bluish papules and nodules which may occur anywhere on the body but preferred sites include the head, neck and scalp. Here, immunohistochemisty analyses are used to positively identify the lesions.

These lesions are typically widely metastatic at the time of presentation; however, not every thyroid cancer must have such grim circumstances, if the clinician were to react in a timely fashion, particularly with medullary carcinoma of the thyroid (MTC).

Pruritis

According to Dr. Heymann, patients and particularly children can oddly present with pruritus on the scapular region in cases of either multiple endocrine neoplasia type 2a (MEN2a) or familial MTC. “If you have a young patient presenting with pruritus localized to the scapular region in the form of either notalgia paresthetica, macular amyloidosis, lichen amyloidosis or biphasic amyloidosis, you should ask about the potential for a family history of MEN2a or familial MTC. “If there is a history of those syndromes in the family, and your adolescent patient develops nostalgia paresthetica, it is likely that the patient has medullary thyroid cancer,” Dr. Heymann tells Dermatology Times.

MTC is a highly fatal malignancy, and a prophylactic thyroidectomy can likely save the patient’s life.

This acute awareness underscores how crucial it is for the dermatologist to associate a seemingly banal cutaneous symptom, such as scapular itch, with thyroid cancer. Dr. Heymann says that if a patient is complaining of itch in that family, and particularly in this constellation, dermatologists need to react very quickly.

Nonspecific signs

Thyroid disease can also be recognized in nonspecific signs such as in hypo- and hyperthyroidism. Telogen effluvium, moist skin, and hyperhidrosis, and pre-tibial myxedema are common cutaneous signs of hyperthyroidism, whereas in hypothyroidism, dry skin and very dry skin (keratoderma), dry nails, and hair loss with madarosis are hallmark cutaneous features of the disease.

However, Dr. Heymann says that dermatologists should sometimes try to think above and beyond these obvious textbook symptoms and think about the associations of thyroid disease with other conditions, notably autoimmune-type disorders.

Autoimmune disease

“Dermatologists should be aware that patients with autoimmune disease of any nature can have an association with autoimmune thyroid disease.

Roughly 20 percent to 40 percent may have thyroid autoantibodies, with a far fewer number actually having thyroid disease; however, these patients have a lifelong risk of developing thyroid disease.

“These associations should always be kept in mind when you are dealing with dermatitis herpetiformis, lupus, alopecia areata, vitiligo and other autoimmune diseases,” Dr. Heymann says.

Syndromes

The Carney complex, Cowden disease and McCune-Albright syndrome are rarely associated with thyroid cancer. Upon recognizing these syndromes, dermatologists should possibly also think about thyroid disease in the context of those syndromes as well.

The Carney complex and Cowden disease are typically associated with adenomas in approximately 60 percent of cases and thyroid carcinoma in roughly 10 percent.

In the literature, there have only been a couple of thyroid cancers reported with McCune-Albright syndrome and about a third of cases can be associated with thyrotoxicosis.

Thyroid function assessment

“On any given day, inevitably somebody in your practice has thyroid disease. We have the opportunity to recognize it, and if they already have the diagnosis, we should be thinking how it can be influencing other dermatologic conditions,” Dr. Heymann says.

Dr. Heymann believes that thyroid function assessment should be considered standard practice in patients with a personal or family history of autoimmune disease, as well as in patients with cutaneous symptoms suggestive of either hyper- or hypothyroid states.

Dr. Heymann has recently edited the textbook Thyroid Disorders with Cutaneous Manifestations, published by Springer, which covers this subject in detail.

Disclosures: US patent 5,951,989: The Use of Topical Thyroid Hormone for the Treatment of Xerosis.