The essential role of anti-thyroid antibodies in chronic idiopathic urticaria.

Background: An autoimmune etiology has been suggested in up to one-third of cases of chronic idiopathic urticaria (CIU), in which it has been proposed that a subset of cases are associated with thyroid autoimmunity. The objective of our present study was to verify the prevalence of thyroid antibodies in the patients with CIU.

Methods: Sixty patients aged 12-51 years, who met criteria for CIU, and 40 aged-matched healthy controls (18 males and 22 females) were participated in this study. Serum anti-thyroid antibodies (ATAs), thyroid hormones, total immunoglobulin E (IgE), and food allergen-specific IgE antibodies were measured. The CIU group was treated with anti-H1 and anti-H2 histamines for 3 weeks.

Results: The total ATA positive rate was 27.3% (33% males and 25% females) in the CIU group. The prevalence of anti-thyroglobulin antibodies, anti-TSH-receptor antibodies, and anti-thyroid peroxidase antibodies were 16.6%, 83.3%, and 8.3%, respectively. The thyroid hormones, T3, and T4, and the TSH were within the normal limits. The radioallergosorbent test was negative for food allergens, and only 18% of the patients had a total IgE concentration >200 IU/mL.

Conclusion: ATAs were found in 27% of the patients with CIU, but these antibodies did not dysregulate thyroid hormone secretion nor did they mediate any clinical manifestations.