Hypothyroidism: Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone. Causes of hypothyroidism include Hashimotot's thyroiditis, subacute thyroiditis, previous thyroid therapy, drug-induced, Pituitary or hypothalamic disease, and iron deficiency. Some common symptoms of hypothyroidism are fatigue, constipation, weight gain, poor appetite, dry, rough skin, coarse hair, hair loss, edema, depression, and elevated cholesterol levels. Treatment of hypothyroidism is generally with medication.