Medical Encyclopaedia › Hashimoto’s thyroiditis (short definition)
In brief: Hashimoto’s thyroiditis is a chronic autoimmune inflammation of the thyroid gland and the most common cause of an underactive thyroid in Germany. Women are affected much more often than men.
What happens in the body?
The immune system forms antibodies against components of the thyroid, above all against thyroid peroxidase (TPO). Over the years, thyroid tissue is destroyed, so that hormone production can decline. A hereditary predisposition plays a role; other autoimmune diseases often occur as well.
Symptoms
At the beginning there are often no symptoms. If an underactive thyroid develops, tiredness, sensitivity to cold, weight gain, constipation, dry skin, hair loss and low mood appear. Rarely, a temporary overactive phase occurs at the start.
Diagnosis
Raised TPO antibodies in the blood and a typical dark (hypoechoic) ultrasound image of the thyroid confirm the diagnosis. The TSH value and free thyroxine show whether the thyroid is still producing enough hormones. Raised antibodies alone without a functional disorder usually do not require treatment, but do require regular check-ups.
Treatment
If the thyroid is underactive, the missing hormones are replaced with levothyroxine; the dose is adjusted according to the TSH value. Stricter target values apply when trying to conceive and during pregnancy. A cure for the inflammation itself is not yet possible. There is only limited evidence of a benefit from selenium preparations; a normal iodine-containing diet is harmless, but high-dose iodine preparations should be avoided.
When to see a doctor?
In the case of persistent tiredness, weight changes without a clear cause, menstrual disorders or difficulty conceiving, a thyroid examination can be useful. Regular laboratory checks are important while taking levothyroxine.
Related terms in the encyclopaedia
Thyroid gland, Hypothyroidism, TSH, Levothyroxine, Autoimmune disease, Selenium, Iodine deficiency, Goitre
Sources
- Deutsche Gesellschaft für Endokrinologie (DGE): Patienteninformationen zu Schilddrüsenerkrankungen, endokrinologie.net
- IQWiG: gesundheitsinformation.de – Gesundheitsinformationen des Instituts für Qualität und Wirtschaftlichkeit im Gesundheitswesen
- Bundesministerium für Gesundheit: gesund.bund.de – Nationales Gesundheitsportal
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor or pharmacist. Last updated: October 2026.