Well, that sounds like a big old pain in the butt. Okay, sorry. Bad joke. But really. That's got to be annoying. It's the same spot at all times? I've never heard of course butt hair causing severe itch . . . that's a little suspect. So, a specialty you may want to consider is a dermatologist. what if it is fungal on the skin? What if it is an allergy of some sort? It would be odd to just show in your butt area but who knows. It does fit patterns for both of those things. How long has the itch been happening?
I know this sounds crazy but have you considered pinworms? They are known to come out at night and causing itching on the butt hole
They are very common to pick up and easily treated
Best way to test would be to put tape on your bum over night and check in the mornings
They are tiny little and white and cause a lot of itching
Sounds like possibly candida. (Over growth of yeast) I went to a functional medicine nurse and was diagnosed with that and they gave me some natural supplements and a diet to get rid of it. Praying