Alopecia areata is a hair loss disorder believed to have an autoimmune origin. It is well established that patients with alopecia areata have an increased risk of other autoimmune conditions, with thyroid disease being the most common. As in the case of vitiligo, it is more common to find thyroid autoantibodies or subclinical hypothyroidism than overt thyroid disease, unless there are clinically suspicious findings. Patients identified as having subclinical hypothyroidism are not currently treated and may even have resolution of the abnormal TSH. Recognizing the risk of associated autoimmune disease has led physicians over time to screen patients with alopecia areata for other diseases. There is no convincing evidence that extensive workups in the absence of specific clinical suspicion improves outcomes for patients, and may in fact beget additional costs, including follow-up for patients screening positive, as well as harms. Although many studies suggest ordering these tests, this is based largely on the increased cosegregation of alopecia areata and thyroid disease and not on improved management strategies or outcomes from having identified an abnormal laboratory test result. Therefore, thyroid function testing, including screening for thyroid autoimmune disease or hypothyroidism, is only indicated for clinical findings such as goiter, slow growth and hypothyroid symptoms, or a strong family history of thyroid disease.