I have itchy anus i regularly shave my anus but starts to get itchy like week or so after i shave it , i was wondering why so itchy a times ?

The ends of the shaved hairs are frequently cut at an angle. As they grow out these angled ends are sharp and cause small pinprick sensations that may itch as they contact the skin. Try using a trimmer instead for more blunt ends.

Worm and similar infestations can cause itchy anus. Check stool for Ova & Parasites and then see PCP or Gastroenterologist about shaving anus which can cause other problems down the line.