Effect of levothyroxine treatment on clinical symptoms and serum cytokine levels in euthyroid patients with chronic idiopathic urticaria and thyroid autoimmunity.

BACKGROUND: Screening for thyroid autoimmunity in patients with chronic idiopathic urticaria (CIU) is generally recommended. However, there are not yet sufficient data as to whether levothyroxine treatment is beneficial for the clinical symptoms of CIU in patients with thyroid autoimmunity.

AIM: We investigated the effect of levothyroxine treatment on clinical symptoms and serum tumour necrosis factor (TNF)-alpha, interleukin (IL)-10 and interferon (IFN)-gamma levels in euthyroid patients with CIU and thyroid autoimmunity.

METHODS: In total, 15 patients with CIU and positive thyroid autoantibodies were randomized to receive either levothyroxine plus 5 mg/day desloratadine (suppression group, n = 8) or 5 mg/day desloratadine alone (control group, n = 7) for 12 weeks. Clinical symptoms of CIU, thyroid hormone levels, thyroid antibodies and serum cytokine levels were assessed at baseline and after the treatment.

RESULTS: There were significant improvements in pruritus score and severity of weals in both groups compared with baseline values, but when the two groups were compared, there was no significant difference in the patients' clinical symptoms. Thyroid antibody titres were not different according to intragroup and intergroup analysis. In the suppression group, serum IFN-gamma and TNF-alpha levels were increased after treatment with levothyroxine compared with baseline values and there was a borderline statistical significance (P = 0.05 for both).

CONCLUSIONS: These results suggest that levothyroxine treatment is not a reasonable option in euthyroid patients with CIU and thyroid autoimmunity. Augmentation of cytokine production after levothyroxine treatment seems to be related to the immunomodulatory effects of TSH-suppressive treatment.