• An autoimmune condition of the thyroid gland (a gland located beneath the larynx). It is caused by the formation of antibodies that attack the thyroid gland and it usually causes hypothyroidism (too little thyroid hormone). Symptoms include fatigue, weight gain, constipation, dry skin, depression, and the inability to exercise. It is more common in females and can run in families.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• Chronic autoimmune thyroiditis, characterized by the presence of high serum thyroid AUTOANTIBODIES; GOITER; and HYPOTHYROIDISM.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• (hashimoto thyroiditis) A chronic, autoimmune type of thyroiditis associated with hypothyroidism.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• (hashimoto thyroiditis) An autoimmune disorder caused by the production of autoantibodies against thyroid tissue. There is progressive destruction of the thyroid follicles leading to hypothyroidism.
  NCI
  U.S. National Cancer Institute, 2021
• (hashimoto thyroiditis) An autoimmune disorder characterized by inflammation and lymphocytic infiltration of the thyroid gland, sometimes associated with reduced thyroid function.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021
• (hashimoto's thyroiditis) A disease in which the body's immune system prevents the thyroid gland from producing enough thyroid hormone.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• (lymphomatous thyroiditis) Progressive enlargement of the thyroid gland, often associated with hypothyroidism.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Hashimoto thyroiditis is chronic autoimmune inflammation of the thyroid with lymphocytic infiltration. Findings include painless thyroid enlargement and symptoms of hypothyroidism. Diagnosis involves demonstration of high titers of thyroid peroxidase antibodies. Lifelong L-thyroxine replacement is typically required.
  Merck Manuals
  Merck & Co., Inc., 2025
• Hashimoto thyroiditis is part of the spectrum of autoimmune thyroid diseases (AITDs) and is characterized by the destruction of thyroid cells by various cell- and antibody-mediated immune processes. This condition is the most common cause of hypothyroidism in the United States in individuals older than 6 years.
  Medscape
  WebMD, 2025
• Hashimoto's disease is a condition in which your immune system attacks your thyroid, a small gland at the base of your neck below your Adam's apple. The thyroid gland is part of your endocrine system, which produces hormones that coordinate many of your body's functions.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research, 2025
• Hashimoto�s syndrome is an autoimmune disease in which a person's immune system mistakenly attacks the thyroid gland, reducing its ability to produce hormones (hypothyroidism). Many people with Hashimoto�s syndrome have no symptoms at first. An early sign of the syndrome may be enlargement of the thyroid (called a goiter), which can...
  NIH Genetic and Rare Diseases
  National Center for Advancing Translational Sciences
• Hashimoto disease, a noninfectious form of inflammation of the thyroid gland (thyroiditis). Hashimoto disease is an autoimmune disorder (i.e., the body reacts to its own tissues as though they were foreign substances). Its onset is insidious, with gradual enlargement of the thyroid gland (a...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025