Screening Guidelines for Thyroid Function in Children With Alopecia Areata.

Importance: The incidence of thyroid disease in children with alopecia areata (AA) has been widely studied with no consensus on whether a true association with AA exists. In addition, screening practices for thyroid dysfunction in children with AA vary widely among clinicians. Objective: To reduce health care costs, eliminate unnecessary testing, and standardize clinical practices, we sought to characterize thyroid function in children with AA to establish guidelines for screening. Design, Setting, and Participants: A single-site retrospective medical chart review was carried out in an outpatient pediatric dermatology clinic in a tertiary referral medical center between January 1, 2008 and January 1, 2016. The study included 298 patients (ages 0-21 years) who received a clinical diagnosis of AA and underwent thyroid function tests. Main Outcomes and Measures: Age at diagnosis of AA, duration of disease, severity, location, and type were documented. Past medical history and family medical history of patients were also recorded. Results of laboratory tests including thyrotropin (formerly thyroid-stimulating hormone [TSH]), free T4 (FT4), triiodothyronine (T3), thyroid peroxidase antibodies (TPO-Abs), and thyroglobulin antibodies (Tg-Abs). Results: During the 8-year period, 298 patients with AA had thyroid function screening. Of those with thyroid screening, patterns of AA included patchy (68%), ophiasis (13%), totalis (9%), and universalis (10%). Severity was determined by percentage of hair loss on the scalp and were divided into mild (30.2%), moderate (32.9%), and severe (36.9%). A total of 59 (20%) patients had abnormalities on thyroid testing results. In this group of patients, hypothyroidism was the most frequent finding 29 (49%), with Hashimoto thyroiditis being the most common cause(24 [41%]). Other abnormalities included hyperthyroidism secondary to Grave disease (12 [20%]) and subclinical thyroid dysfunction (7 [12%]). Whereas age, duration of disease, pattern of alopecia, and diagnosis of autoimmune diseases had no significant association with abnormal thyroid findings, a personal history of Down syndrome (P = .004), atopy (P = .009), and family history of thyroid disease (P = .001) did. Conclusions and Relevance: We recommend that routine thyroid function screening should be restricted to AA patients with a medical history of Down syndrome, personal history of atopy, a family history of thyroid disease, or clinical findings (goiter) suggestive of potential thyroid dysfunction in the individual patient.