Autoimmune Thyroid Diseases in Chronic Spontaneous Urticaria: The Role of Hormones, Anti-Thyroid Antibodies, and Ultrasound.

Background/Objectives: Chronic spontaneous urticaria (CSU) is an immune-mediated skin disorder, with increasing evidence suggesting its association with autoimmune thyroid diseases. The presence of antithyroid antibodies (anti-TPO and anti-TG) and autoimmune thyroid disease indicates shared immunological mechanisms in the pathogenesis of both conditions. This study examines the prevalence of autoimmune thyroid changes in patients with CSU. Methods: The study was conducted as a combined retrospective-prospective observational analysis. It included 43 patients with CSU and 50 healthy participants in the control group. Thyroid hormone levels (TSH, T3, T4), anti-TPO and anti-TG antibodies, as well as ultrasound characteristics of the thyroid gland, were analyzed. Results: In patients with CSU, a higher prevalence of hypothyroidism (27.9% vs. 4% in the control group), hypertension, asthma, and diabetes were observed. Elevated levels of anti-TPO antibodies were found in 51.2% of CSU patients, compared to only 6% in the control group (p < 0.001). Similarly, anti-TG antibodies were increased in 41.9% of CSU patients, compared to 4% in the control group. Additionally, ultrasound analysis revealed significant differences in thyroid morphology, with a heterogeneous structure observed in 72.1% of CSU patients, compared to only 14% in the control group (p < 0.001). Nodular changes were present in 34.88% of CSU patients, whereas the prevalence in the control group was only 6% (p < 0.001). Conclusions: Our results confirm a significant association between CSU and autoimmune thyroid diseases, including a high prevalence of anti-TPO and anti-TG antibodies, hypothyroidism, diffuse heterogeneity, and nodular changes. Additionally, elevated T3 hormone levels were common among CSU patients, while T4 levels did not differ significantly from those in the control group.