 [ Symptoms ] i was diagnosed mitrial valve prolapse hard to focus and concentrate need ct or mri [ Disease ] any medication including thyroid medications can cause an allergic reaction such as hives the incidence of hives with thyroid medication though is very low however there is a known association between hives and thyroid antibodies about a quarter of patients with long term hives chronic urticaria have antibodies to thyroid tissue and many of these patients are found to have low thyroid levels the patients who had the worst hives were also the ones more likely to have antibodies to thyroid tissue hives patients can also have antibodies to other immune mediated diseases such as lupus unfortunately treating the thyroid condition does not eliminate the hives