Silent Thyroiditis
Silent thyroiditis — also called painless or lymphocytic thyroiditis — is an inflammation of the thyroid that causes thyroid hormone to leak into the blood without the pain of subacute thyroiditis.
Like subacute thyroiditis, it usually passes through a thyrotoxic phase and then a hypothyroid phase before recovery, but the absence of pain makes it harder to recognise.
Last medically reviewed: 15 November 2025
What it looks like
People present with symptoms of an overactive thyroid — palpitations, anxiety, tremor, heat intolerance — but the gland is not tender. Blood tests show thyrotoxicosis with a low radioactive iodine uptake, confirming that the gland is leaking hormone rather than overproducing it.
A hypothyroid phase commonly follows weeks later as hormone stores run out.
Causes and triggers
Silent thyroiditis is most often an autoimmune process. It occurs commonly after pregnancy (postpartum thyroiditis), and can be triggered by certain medications such as interferon, lithium or amiodarone.
It may also occur without an obvious trigger.
Management
Treatment focuses on symptoms: beta-blockers for the thyrotoxic phase and, if needed, temporary levothyroxine for the hypothyroid phase. Antithyroid drugs are not appropriate because the gland is not overproducing hormone.
Thyroid function is monitored until it stabilises, since a proportion of people go on to develop permanent hypothyroidism.
Frequently asked questions
How is silent thyroiditis different from Graves’ disease?
Both cause thyrotoxicosis, but in silent thyroiditis the gland leaks stored hormone and iodine uptake is low, whereas in Graves’ disease the gland overproduces and uptake is high. Treatment differs accordingly.
Does it come back?
It can recur, particularly with a further pregnancy or trigger. Many people recover fully, but lifelong hypothyroidism can develop.
Do I need antithyroid medication?
No — antithyroid drugs block hormone production and do not help when the gland is leaking stored hormone. Treatment is supportive.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
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