I am suffering frm alopecia areata frm the age of 8, now m 18.i visit many doctors.but didn't help.use injection solutions like minixodil.but didn't help?

You have a choice: Alopecia areata is often impossible to treat effectively. You are almost a grown man and you have the option of embracing what has happened to you. Good muscular development -- mass, definition, or both -- take precedence over hair, anywhere and everywhere. Some of the most outstanding physical specimens of men -- from vin diesel to damien walters -- are hairless by choice. Hit the gym.

Simvistatin,laser: Two treatments that work for resistant cases is the excimer laser used for psoriaisis and vitiligo as well as oral simvistatin a cholesterol lowering drug which works to decrease inflammation and allow regrowth of hair in alopecia areata. The combination can work in resistant cases.

Unfortunate.: Sounds like you have tried it all. Early age of onset and persistence of disease beyond 1 year are both poor prognostic indicators. It may be that your hair does not regrow.