Chronic urticaria: association with thyroid autoimmunity.

BACKGROUND: Though autoimmune phenomena have been regularly associated with chronic urticaria in adults, data in children are sparse. AIM: To describe our experience with children and adolescents with chronic urticaria and autoimmunity. METHODS AND
RESULTS: Of 187 patients referred for evaluation of chronic urticaria during a 7.5 year period, eight (4.3%), all females aged 7-17 years, had increased levels of antithyroid antibody, either antithyroid peroxidase antibody (n = 4, >75 IU/ml), antithyroglobulin antibody (n = 2, >150 IU/ml), or both (n = 2). The duration of urticaria was four months to seven years. Five patients were euthyroid, one of whom was found to have increased antithyroid antibody levels five years after onset of the urticaria. One patient was diagnosed with Hashimoto thyroiditis three years before the urticaria, and was receiving treatment with thyroxine. Two other hypothyroid patients were diagnosed during the initial work up for urticaria (thyroxine 9.2 pmol/l, thyroid stimulating hormone (TSH) 40.2 mIU/l) and five years after onset of the urticaria (thyroxine 14 pmol/l, TSH 10.3 mIU/l). Both were treated with thyroxine but neither had remission of the urticaria. Five patients had a low positive titre of antinuclear antibodies.
CONCLUSION: Children with chronic urticaria should be screened periodically for thyroxine, TSH, and antithyroid antibodies, as thyroid autoimmunity and hypothyroidism may appear several years after onset of the urticaria.