What condition/disease can cause (curable) tinnitus?

Wax: Wax accumulation is by far most common cause of tinnitus. It's important to clarify if it is in both ears or one ear. Tinnitus is an indication of a decrease in hearing. This can be caused by wax blockage, fluid behind the ears, problem with the ear drum or damage to the nerve. New onset persistant tinnitus in one ear lasting more than 24 hours should get looked at by an ent.