An Analysis of Thyrotropin Levels in Patients With Nonscarring Alopecia: A Single-Center Retrospective Comparative Study.

Abstract

Objective: To compare thyrotropin (TSH) levels across nonscarring alopecia (NSA) subtypes-alopecia areata (AA), telogen effluvium (TE), and androgenetic alopecia (AGA)-in a primary analysis of all patients, a secondary analysis of euthyroid patients stratified into low-normal (0.5-2.5 mIU/L) and high-normal (2.5-4.5 mIU/L) categories, and a tertiary analysis of patients with thyroid dysfunction.

Methods: A retrospective chart review was conducted on patients diagnosed with AA, TE, or AGA at a single academic dermatology department between August 2017 and August 2024. TSH values were drawn within 3 months of the initial visit, and patient demographics were extracted from the electronic medical record. Patients with thyroid dysfunction were excluded from the secondary analysis. TSH values within the euthyroid range were stratified into low-normal and high-normal categories. A tertiary analysis of patients with frank thyroid dysfunction was later conducted. Descriptive statistics, Kruskal-Wallis tests, and Bonferroni-corrected pairwise comparisons were performed.

Results: Among the 1,411 patients initially identified, most TSH values were within the euthyroid range. In a secondary analysis of 1,291 euthyroid patients, there was no significant difference in TSH distribution across NSA subtypes, including when stratified into low-normal vs high-normal categories. Among patients with thyroid dysfunction (8.5%), those with TE had the highest relative proportions of both hypothyroidism (5.0%) and hyperthyroidism (5.5%). Black or African American patients with AA and TE had lower mean TSH levels than White patients; however, this was not observed in AGA.

Limitations: Limitations of this study include the retrospective design and the potential for incomplete or biased medical records.

Conclusion: TSH levels among patients with NSA did not vary significantly based on NSA subtype. Racial differences in mean TSH were observed in AA and TE, but the clinical significance remains uncertain.