Hashimoto’s disease is a condition characterized by chronic inflammation of the thyroid gland, also called chronic thyroiditis. Among the diseases of the thyroid, Hashimoto’s disease is much more common in women than men, with a male-to-female ratio falling between 1: 20 and 1:30. When comparing age groups, Hashimoto’s disease is common in people in their late 20s or older, particularly those 30-50. The disease is rare in toddlers and school children.
Hashimoto’s disease is an autoimmune disorder, but it is still not clear what triggers its development. Inflammation due to an autoimmune disorder may cause swelling of the thyroid that leads to thyroid dysfunction.
Not all patients with Hashimoto’s disease develop hypothyroidism. While chronic inflammation of the thyroid gland is characteristic of Hashimoto’s disease, thyroid function may remain normal when inflammation is mild. However, progression inflammation worsens thyroid function, leading to hypothyroidism. For patients with Hashimoto’s disease, approximately 10% have clear symptoms of hypothyroidism, 20% have mild asymptomatic hypothyroidism, and the remaining 70% have normal thyroid function.