Oral Lichen Planus and Thyroid Disease: A Case-Control Study

Background: Oral lichen planus (OLP) is a chronic inflammatory condition that primarily affects the oral mucosa. While the exact cause of OLP remains unclear, recently, there has been particular interest in researching the potential link between OLP and thyroid gland disorders. Methods and Results: A total of 100 subjects participated in our research. Among them, 50 were patients (80% women and 20% men) diagnosed with OLP (the main group [MG]), and 50 subjects (60% women and 40% men) with various other oral mucosa concerns (aphthous stomatitis, burning mouth syndrome, herpetic stomatitis, and geographic tongue) comprised the comparison group [CG]. All participants underwent a comprehensive assessment of thyroid function, which included the measurement of free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), thyroid peroxidase antibodies (TPO-Ab), and an ultrasound examination of the thyroid gland performed by an endocrinologist. Our results reveal a noteworthy gender-based difference in the occurrence of mucosal disorders, indicating a predominance of females. MG had a significantly higher prevalence of hypothyroidism, with 46% of patients affected. In contrast, in CG, the prevalence of hypothyroidism was lower, at 16%, and this difference was statistically significant (P=0.0012). In MG, 50% of cases were found to be in a euthyroid state. In contrast, in CG, a larger proportion (80%) of patients were in a euthyroid state, and this difference was statistically significant (P=0.0017). Conclusion: Our study has identified a significant and positive association between hypothyroidism and OLP. We recommend that individuals diagnosed with OLP, especially women, consider undergoing routine screening for thyroid disease as part of their healthcare regimen.