Tinnitus is a disorder of the hearing system that affects millions of people worldwide. It is characterized by an intermittent or continuous buzzing or ringing in the ear. Other people suffering from tinnitus even complain of clicking, hissing, whooshing sounds, and roaring, screaming noises. Tinnitus is caused by many underlying conditions. Tinnitus can also be caused by a serious case of carotid artery aneurism, or it may be due to giant cell arteritis or vasculitis.