Urticaria is one of the most frequent dermatosis, being its prevalence in general population estimated about 20%. This prospective case-control study was aimed at determining the prevalence of thyroid autoimmune disorders in a cohort of patients with chronic urticaria (CU), all living within an area with mild-to-moderate iodine deficiency. Fifty four consecutive patients affected by CU were recruited and compared to 108 healthy controls. Assessment of the thyroid function included measurement of serum concentrations of TSH, FT3, FT4, anti-thyreoglobulin (anti-TG) and anti-peroxidase (anti-TPO) antibodies. Ultrasound scan of the thyroid gland was performed in all subjects using a 7.5 MHz linear transducer. All subjects were followed up for 6 months. The prevalence of thyroid antibodies was significantly higher in our cohort of patients with CU than in controls (22% vs. 6.5 %). Hashimoto's thyroiditis was also more frequent in patients than controls (18.5% vs. 1.8%). These frequencies do not differ from those previously reported by some other authors and confirm the association between CU and thyroid autoimmunity also in the area of iodine deficiency. However, presence of antibodies or thyroiditis does not seem to influence clinical course of CU. These results suggest that screening for thyroid function may be useful in all the patients with CU.
Keywords: Hashimoto's thyroiditis; iodine deficiency; urticaria.