Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis, is an autoimmune condition that affects the thyroid gland. In Hashimoto's thyroiditis, the body's immune system mistakenly attacks and damages the thyroid, leading to inflammation and interference with its normal function.

The exact cause of Hashimoto's thyroiditis is not fully understood, but it is believed to involve a combination of genetic factors and environmental triggers. The condition is more common in women and tends to develop gradually over time.

Some common signs and symptoms of Hashimoto's thyroiditis include fatigue, weight gain, constipation, sensitivity to cold, muscle aches, joint pain, dry skin, hair thinning, and depression. As the disease progresses, it can lead to an underactive thyroid (hypothyroidism), resulting in additional symptoms such as sluggishness, difficulty concentrating, and an enlarged thyroid gland (goiter).

Diagnosis of Hashimoto's thyroiditis is typically based on a combination of symptoms, physical examination, blood tests to measure thyroid hormone levels and antibodies, and imaging studies if necessary.

Treatment for Hashimoto's thyroiditis aims to manage the symptoms and prevent complications. This usually involves lifelong thyroid hormone replacement therapy, typically with synthetic thyroid hormone medication (levothyroxine). Regular monitoring of thyroid hormone levels is important to ensure that the dosage is appropriate.

In addition to medication, lifestyle modifications such as a healthy diet, regular exercise, and stress management techniques may be beneficial in managing the condition.