Thyroiditis

Hashimoto's disease, also known as chronic lymphocytic thyroiditis, is a condition in which your immune system attacks your

thyroid

. Inflammation from Hashimoto's disease often leads to an underactive thyroid gland (hypothyroidism). Hashimoto's disease, also known as chronic lymphocytic thyroiditis, is an often leads to an underactive thyroid gland (hypothyroidism). Hashimoto's disease is the most common cause of hypothyroidism. It primarily affects middle-aged women but can also occur in men and women of any age and in children.