Hashimoto's disease, also known as "Hashimoto thyroiditis," "chronic lymphocytic thyroiditis," "chronic autoimmune thyroiditis," or "struma lymphomatosa," is a non-infectious form of thyroiditis. An autoimmune condition, Hashimoto disease causes the body to react to its own tissues as if they were foreign substances. The gradual enlargement of the thyroid gland, which is known as a goitre, and the gradual decrease in production of thyroid hormone are signs of its insidious onset. Symptoms and signs of hypothyroidism, or both, and symmetrical rubbery enlargement of the thyroid gland are typical findings. Thyroid deficiency and gradual thyroid enlargement are common features of the disease's natural course.