Hyperthyroidism, also known is an overactive thyroid, is when the thyroid gland, a butterfly shaped gland in the front of your neck, makes too much thyroxine and triiodothyronine, two types of hormones. Thyroid hormones affect the function of many of your body’s organs.

One of the symptoms of hyperthyroidism is goiter, an enlargement of the thyroid gland. Goiter can increase pressure on your throat, making it feel like you have a lump in your throat that can make it hard to swallow, sometimes causing pain and soreness.

Additionally, one of the causes of hyperthyroidism, thyroiditis, can also cause a sore throat. Thyroiditis is an inflammation of the thyroid that can results from a viral infection.

Sore throat can also be an emergency side effect of certain medications for hyperthyroidism.

Serious side effects

Contact your doctor immediately if you are taking thionamides for hyperthyroidism and experience the following side effects:

  • high temperature
  • sore throat
  • persistent cough

These are symptoms of agranulocytosis, a sudden drop in your white blood cell count, which is a rare side effect of this drug type.

Goiter can put pressure on the surrounding structures in and around your neck, such as your trachea or esophagus. While goiter itself is often painless, it can lead to a sore throat or difficulty swallowing.

Thyroiditis causes an enlarged thyroid gland with pain or tenderness that develops over 24 to 48 hours. Symptoms include:

  • sore throat
  • fever
  • fatigue
  • painful swallowing
  • aches and pains, including in the neck
  • symptoms of temporary thyroid overactivity, including:
    • weight loss even as your appetite increases
    • rapid or irregular heartbeat
    • anxiety and irritability
    • trouble falling or staying asleep
    • shaky hands and muscle weakness
    • sweating and trouble tolerating heat
    • frequent bowel movements

A common drug class called thionamides are used to treat hyperthyroidism and work by halting the production of thyroid hormones. The most common types are carbimazole (Camazol, Neomercazole) and propylthiouracil (Propyl-Thyracil, PTU, Thyrozol).

These medications are typically taken for 12 to 18 months, until thyroid levels are stabilized. Some people need to take them for years. Typical temporary side effects of thionamides include:

  • high temperature
  • headaches
  • achy joints
  • rash
  • upset stomach

Another rare side effect is a drop in white blood cell count, called agranulocytosis. Symptoms of this are high temperature and sore throat in addition to a persistent cough. You should contact your doctor right away if you experience these symptoms.

It’s important to speak with a medical professional if you notice a lump in your neck or changes in your voice, or have persistent sore throat or difficulty swallowing. While a sore throat can be associated with hyperthyroidism, it has many potential causes.