Thanks for query,
Fissure is not specific with age.
You gets fissure due to brake of your rectal mucous membrane
due to friction of hard stool gets infection & later on bleeding leads to recurrent infection & when heals due to fibrous tissue it has less elasticity so leads to more friction.
Some times it is associated with piles also.
The first & fore most rule of fissure treatment is you should have a loose stool
so that it passes easily & no friction arises & you gets healing of wound.
Take more leafy vegetables,a mild laxative,along with mild anti inflammatory medicine with anti anerobic infection medicine will help you.
You should take warm water sitting after every act of defecation & then apply xylocain containing cream will heal the wound.