In case of allergic reaction to hyperthyroid medication, the patient may choose to continue taking the medication, switch to other medication, switch to radioactive iodine treatment or surgery according to the condition of the patient. The drugs commonly used in the treatment of hyperthyroidism are propylthiouracil and methimazole, and some patients may have allergic reactions, which may be manifested as skin rashes, itching of the skin, etc. When allergic reactions occur, different measures can be taken under different circumstances. 1. Continue to take medication: Antithyroid medication is the basis of hyperthyroidism treatment, therefore, when the allergic reaction is mild, you can not stop taking the medication and give antihistamines such as loratadine as appropriate. 2. Switching to other drugs: If the allergic symptoms are serious, you can switch to another antithyroid drug, such as methimazole for propylthiouracil when you are taking methimazole, but need to be under the guidance of a doctor. 3. Radioactive iodine therapy or surgery: when the allergic reaction is more serious, the drug should be stopped immediately, and when it is not possible to change to another anti-thyroid drug, radioactive iodine therapy or surgery is chosen as a way to follow up the treatment of hyperthyroidism. Patients who are allergic to hyperthyroid medication should be treated for subsequent hyperthyroidism under the guidance of a medical professional.