Well if you play some instrument using your mouth, that very much causes "EC". you shoul stop it immediately. i have heard many ppl have cured it completely, its just that our body is not responding to the treatments and we don't know the underlying cause(if any)that is triggering this. i also had a month long chat with one person who cured it completely.
Don't worry your ailment'll be cured some day if not immediately. patience would be greatly instrumental in this. Wishing you luk