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Certain children with alopecia areata (AA) should undergo routine thyroid function screening, researchers suggested.

In an analysis of 298 individuals with AA (all ≤21 years) 20% (59) had abnormal findings on thyroid testing, with hypothyroidism as the most common form (49% or 29) as a result of Hashimoto thyroiditis (41% or 24). Other thyroid abnormalities reported in the cohort included hyperthyroidism due to Grave disease (20%, 12), as well as subclinical thyroid dysfunction (12%, 7), according to Deepa Patel, BS, of The Children's Hospital of Philadelphia, and colleagues.

There was no link reported between age, disease duration, autoimmune disease, nor pattern of alopecia with thyroid dysfunction among kids with AA, they wrote in .

However, Patel's group did find a significant association with Down syndrome and thyroid dysfunction in this population (P=0.004). This isn't surprising, as the authors note that AA -- a nonscarring form of hair loss -- is rather common, affecting up to 9% of among those with Down syndrome, in addition to an increased prevalence of thyroid disease.

A family history of thyroid disease (P=0.001) was also significantly associated with thyroid dysfunction in the AA population, as well as atopy (P=0.009). The authors noted this is not surprising, because it's been suggested that "the dysfunction of T regulatory cells present in atopic patient may contribute to the development of autoimmune diseases such as AA and thyroid disease."

Based on these findings, the authors recommend that those with Down syndrome, atopy, or a familial history of thyroid disease should undergo a thyroid screening with TSH and free T4 at the initial signs of AA.

"If abnormalities are detected in either of these values, we then recommend ordering antibody (TPO-Abs or Tg-Abs) tests for potential autoimmune causes of thyroid dysfunction," they wrote. However, it is important that biotin supplementation be stopped at least 48 to 72 hours prior to thyroid screening, for it could confound results of blood tests.

In the absence of these risk factors and anything notable in a physical examination, no thyroid testing should be completed, the group advised.

"Future studies should further investigate the potential role of T3 to ensure that AA patients with thyroid dysfunction are receiving appropriate treatment," they concluded.

Click for the American Association of Clinical Endocrinologists' clinical practice guidelines for thyroid disorders.

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