Hypothyroidism may be caused by damage or injury to the thyroid. This may happen with:
- Disorder of the immune system
- Congenital defects of the gland or how it works
- Surgery, medical procedures, or radiation therapy for thyroid treatment
It may also be caused by:
- Problems with pituitary glands that sends signal to the thyroid
- Iodine deficiency—rare in the US, iodine is needed to make thyroid hormones
In some people, the cause may remain unknown.
Hypothyroidism is more common in women. It is also more common in those aged 65 years and older. Other factors that may increase your chance of hypothyroidism include:
- Family history of hypothyroidism
- Recently gave birth, especially if you had hypothyroidism before
- Surgery, radiation therapy, or radioablation in the neck region
- Autoimmune diseases, such as systemic lupus erythematosus, celiac disease, type 1 diabetes, or rheumatoid arthritis
Symptoms may not always appear. In those that have symptoms, hypothyroidism may cause:
- Coarse, brittle hair, and hair loss
- Facial puffiness
- Dry skin
- Swollen hands or feet
- Cold intolerance
- Weight gain
- Achy feeling all over
- Depression and irritability
- Memory loss
- Difficulty concentrating
- Blurred vision
- Menstrual abnormalities or infertility
Symptoms of severe or long-term hypothyroidism causes:
- Slow heart rate
- Depressed breathing
- Hypothermia—low body temperature
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
Edits to original content made by Denver Health.
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a (Hashimoto's Thyroiditis; Underactive Thyroid)
American Thyroid Association https://www.thyroid.org
Office on Women's Health https://womenshealth.gov
Health Canada https://www.canada.ca
Thyroid Foundation of Canada http://www.thyroid.ca
Escobar-Morreale HF, Botella-Carretero JI, Escobar del Rey F, et al. Treatment of hypothyroidism with combinations of levothyroxine plus liothyronine. J Clin Endocrinol Metab. 2005;90(8):4946-4954.
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Surks MI, Ortiz E, Daniels GH, et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA. 2004;291(2):228-238.
Thyroid hormone treatment. American Thyroid Association website. Available at: https://www.thyroid.org/thyroid-hormone-treatment. Accessed December 15, 2017.