Why does my anus itch where the line comes out ?

Anal itch: Anal itching is rather common and can be caused by perianal dermatitis, pinworms(usually in children), fissures, too little or too much hygiene, friction, reaction to soaps,etc. Avoid excessive or vigorous anal wiping and after a few wipes, wash with warm water, pat dry and apply a corticosteroid ointment.. If no relief see your MD or a proctologist.