The thyroid is the gland in your neck associated with your metabolism—the processes by which your body makes use of energy. Autoimmune thyroid disease is common in lupus. It is believed that about 6% of people with lupus have hypothyroidism (underactive thyroid) and about 1% have hyperthyroidism (overactive thyroid). A thyroid gland that is functioning improperly can affect the function of organs such as the brain, heart, kidneys, liver, and skin. Hypothyroidism can cause weight gain, fatigue, depression, moodiness, and dry hair and skin. Hyperthyroidism can cause weight loss, heart palpitations, tremors, heat intolerance, and eventually lead to osteoporosis. Treatment for both underactive and overactive thyroid involves getting your body’s metabolism back to the normal rate. Hypothyroidism is usually treated with thyroid hormone replacement therapy. Hyperthyroidism is treated with anti-thyroid medications or radioactive iodine.