Thyroid Function, Inflammation, and HDL-Cholesterol in Women with Acne: A Real-World Cross-Sectional Study Integrating Biochemistry and Thyroid Ultrasound

<b>Background:</b> Acne in adult women is increasingly recognized as a condition with systemic endocrine-metabolic correlates. Evidence linking acne to thyroid-related abnormalities and cardiometabolic risk markers remains mixed, and integrated real-world evaluations combining thyroid biochemistry, ultrasound metrics, inflammatory indices, and lipid profile are limited. <b>Methods:</b> We performed a cross-sectional observational analysis of 80 women with acne who underwent routine laboratory testing and thyroid ultrasound assessment. Thyroid status was defined using TSH (reference 0.4-4.5 mIU/L) and free T4 (0.8-1.8 ng/dL), with an additional TSH-only sensitivity definition (high TSH >4.5 mIU/L). Low HDL-cholesterol (HDL-C) was defined as <50 mg/dL. Group comparisons used Mann-Whitney U tests with Hodges-Lehmann shifts; associations were summarized using odds ratios (ORs) with Fisher's exact tests; correlations used Spearman's ρ (TSH log-transformed for correlation analyses) with confidence intervals. Multiple testing was controlled within panels using Benjamini-Hochberg FDR. Analyses were complete-case per comparison. <b>Results:</b> Thyroid dysfunction and metabolic-inflammatory abnormalities were common in this cohort. Low HDL-C was more frequent in thyroid dysfunction, and in the TSH-only sensitivity analysis, high TSH (>4.5 mIU/L) was strongly associated with low HDL-C (OR 13.13, 95% CI 1.48-116.04; <i>p</i> = 0.020). In a minimal adjusted model including NLR, high TSH remained associated with low HDL-C (adjusted OR 12.93, 95% CI 1.44-115.70; <i>p</i> = 0.022). HDL-C showed an inverse association with NLR (ρ = -0.28; <i>p</i> = 0.023). Endocrine profiling suggested a positive association between ACTH and log(TSH) (ρ = 0.62; <i>p</i> = 0.004), although this did not remain significant after FDR correction. Thyroid ultrasound metrics showed limited correspondence with thyroid biochemistry. <b>Conclusions:</b> In women with acne, elevated TSH is associated with substantially higher odds of low HDL-C, independent of inflammatory burden as proxied by NLR, while thyroid ultrasound morphology contributes limited functional information. These findings support integrated thyroid-metabolic assessment in adult female acne and motivate prospective studies incorporating acne severity measures and standardized testing to clarify clinical implications.