Swollen Legs and Puffy Face
In hypothyroidism, tissue changes can cause puffiness around the eyes and face and swelling of the legs. This is different from the sudden swelling of heart or kidney disease, but it should still be assessed.
The swelling develops gradually and is usually accompanied by other symptoms of an underactive thyroid.
Last medically reviewed: 15 November 2025
Why it happens
Low thyroid hormone alters the tissue matrix, allowing fluid and proteins to accumulate in the skin — a change called myxoedema. It produces a characteristic puffy face, thickened skin and non-pitting swelling of the legs.
Reduced heart pumping and kidney effects can add to fluid retention in more severe cases.
When to seek urgent help
Sudden or one-sided leg swelling, breathlessness, or chest pain can indicate a blood clot or heart problem and needs urgent assessment — these are not typical thyroid symptoms.
Progressive drowsiness, confusion or very low body temperature in someone with hypothyroidism is a medical emergency.
Treatment
If hypothyroidism is the cause, levothyroxine usually resolves the swelling over weeks to months. Diuretics are not the answer unless another cause of fluid retention is present.
Frequently asked questions
Can hypothyroidism cause swollen legs?
Yes — it can cause gradual puffiness of the face and non-pitting swelling of the legs, which improves with thyroid hormone replacement.
Is puffy swelling dangerous?
The gradual swelling of hypothyroidism is not usually dangerous, but sudden or one-sided swelling, breathlessness or chest pain needs urgent assessment.
How long until the swelling goes?
It usually improves over weeks to months once thyroid hormone levels are corrected.
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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