Hashimoto's thyroiditis is an autoimmune condition in which the immune system gradually damages the thyroid gland in the neck. It is the most common cause of an underactive thyroid in countries with enough iodine in the diet, and it affects women about seven to ten times more often than men.
Many people have thyroid antibodies for years with normal hormone levels and need only monitoring. Once the gland fails, a daily levothyroxine tablet replaces the missing hormone reliably. It does not switch off the autoimmune process, and no treatment has been proven to do so.
Symptoms
- Tiredness and needing more sleep
- Feeling cold when others are comfortable
- Weight gain of a few kilograms and constipation
- Dry skin, brittle hair and hair thinning
- Heavier or irregular periods and difficulty conceiving
- Low mood, slowed thinking and poor memory
- A painless swelling or fullness at the front of the neck
Causes and risk factors
The immune system produces antibodies against thyroid peroxidase and thyroglobulin, and white cells infiltrate the gland. Why this starts is not fully known. It runs in families and occurs more often alongside type 1 diabetes, coeliac disease, vitiligo, pernicious anaemia and rheumatoid arthritis, and in Down and Turner syndromes. Pregnancy and the year after delivery, high iodine intake, and medicines such as amiodarone, lithium, interferon and cancer immunotherapy can trigger or reveal it.
How it is diagnosed
- TSH and free T4 blood tests: A raised TSH with low free T4 means overt hypothyroidism. A raised TSH with normal T4 is subclinical and is often rechecked in 2 to 3 months before deciding on treatment.
- Thyroid antibodies: Anti-TPO antibodies are positive in about nine in ten cases and confirm the autoimmune cause. Levels do not need repeating and do not guide the dose.
- Thyroid ultrasound: Shows a characteristic patchy, darker gland. It is needed mainly when the gland is enlarged or a lump is felt.
- Fine needle biopsy: Only for a distinct nodule with suspicious ultrasound features, since nodules can coexist with Hashimoto's.
Treatment options
- Monitoring alone: Positive antibodies with normal TSH need a blood test every 6 to 12 months, sooner if planning pregnancy.
- Levothyroxine: A once-daily tablet taken on an empty stomach, away from iron, calcium and coffee. The dose is adjusted by TSH every 6 to 8 weeks until stable, then checked yearly.
- Treatment of subclinical hypothyroidism: Offered when TSH is persistently above about 10, or lower with symptoms, goitre, or pregnancy plans. Less benefit is seen in people over 70.
- Pregnancy management: Dose usually rises by a quarter to a half as soon as pregnancy is confirmed, with TSH checked every 4 weeks in the first half.
- Surgery: Rarely needed, for a large goitre that presses on the windpipe or a suspicious nodule.
When it is urgent
Severe untreated hypothyroidism can, rarely, lead to myxoedema coma. Call emergency services locally for marked drowsiness or confusion, a very slow pulse, low body temperature or slow shallow breathing in someone with known or suspected thyroid failure. Chest pain or a racing irregular pulse after a dose increase also needs prompt review.
Travelling to Türkiye for treatment
Hashimoto's is managed with a tablet and periodic blood tests, which any local doctor can provide, so it is a poor reason to travel. A visit can reasonably include a one-off endocrine review with ultrasound, particularly if you have a goitre or nodule, or a check that your thyroid is well controlled before fertility treatment or surgery you are travelling for.
Send your reports, scans and a short history and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Will I need levothyroxine for life?
If your thyroid has become underactive because of Hashimoto's, usually yes. The dose may change with weight, pregnancy and age.
Do gluten-free diets or selenium help?
A gluten-free diet helps only if you also have coeliac disease. Selenium can lower antibody levels in some studies but has not been shown to improve symptoms or thyroid function, so it is not routinely advised.
Why do I still feel tired with a normal TSH?
Tiredness has many causes. It is worth checking iron, vitamin B12, vitamin D, sleep and mood, and confirming that tablets are taken correctly. Combination T3 therapy has limited evidence and is a specialist decision.
Does Hashimoto's raise my cancer risk?
There is a small association with thyroid lymphoma, which is rare, and a debated link with papillary cancer. A rapidly enlarging gland should always be examined.