I have this irritated sudden itch that lasts a second?

So my anus was itchy I’m 23 years old male and I got some mary gold creme and hemorrhoid creme these didn’t work, so I went to the dermatologists, he checked my anus but he couldn’t see anything as he told me, so he prescribed me some cortizonsteroid creme elocom. Now I use this for 2 days now and my anus didn’t get better. I have this irritated sudden itch pinch/electric shock feel that lasts like 2 sec in that 1 sec it gets stronger and stronger then 1 sec it fades… there is a buildup until it hits max. I don’t know what it is as my dermatologist couldn’t find anything. Even after I shower I still have this it can’t be worm. What to do?

Age: 23
Medications: Elocom 2hydro, Preperation H and Reparon, Marigold.