Bcoz it's a chronic condition one has to keep it under control by judicious use of medication under physician perview. Any acute exacerbation only, needs aggressive approach to the condition. Unfortunately we don't know what is the exact cause hence it is hard to expect get cured. Now a wide range of safe medication can help one to lead a near normal life. Its like We need to get over the condition to keep it under our control rather than to get succumbed to it.