Beyond the Infection: Decoding the Biochemical and Hematological Fingerprint of Post-COVID-19 Hair Loss

INTRODUCTION: Post-viral alopecia is a prevalent sequela of SARS-CoV-2 infection, yet its biochemical correlates remain poorly defined. This study aimed to elucidate the hematological and metabolic parameters associated with hair loss in patients with a history of COVID-19 compared to unexposed controls.
METHODS: This retrospective case-control study included 366 adult outpatients presenting with alopecia (101 with prior SARS-CoV-2 infection; 265 without). Comprehensive clinical and laboratory data, encompassing blood counts, biochemical panels, and thyroid indices, were evaluated. Data were subjected to univariate and multivariable logistic regression models. A stringent Bonferroni correction.
RESULTS: Univariate comparisons revealed significantly elevated serum iron, AST, and MCV levels, alongside altered thyroid profiles in the COVID-19 (+) cohort (p < 0.05). However, following multivariable adjustment for baseline confounders, notably a paradoxically higher chronic comorbidity burden in the control group, the initial significance of these parameters was attenuated. Serum iron remained a robust, strictly hypothesis-generating, associative marker (p < 0.001), whereas TSH showed a marginal trend (p = 0.058).
DISCUSSION AND CONCLUSION: The biochemical footprint of post-COVID-19 hair loss highlights altered iron homeostasis rather than sustained, broad-spectrum systemic inflammation. While our findings are hypothesis-generating rather than mechanically definitive due to the retrospective design, they underscore the clinical utility of targeted metabolic screening in primary care to optimize post-viral alopecia management.

Keywords: Post-COVID-19, hair loss, telogen effluvium, biomarkers, iron, TSH.