I'm a male and facing this problem for about 5-7 years, didn't know earlier the reason, therefore kept suffering:(
I'm doing parasite cleanse for 15 months, so expelled a lot of biofilm, hopefully can get rid of that completely.
Taking Pau D'Arco for yeast/candida, and a big list of herbs everyday coupled with enema. It also includes coconut oil. So I'm hoping that is taking care of yeast and biofilm.
Have obstinate pinworm infection, so trying to take herbal treatment for that too.
However this itching has been going much before all these started.
To answer specifically, lower part of penis (something that is connected to body), and pelvic region has itching. Also the upper part of thighs (near the pelvic region) has this problem. So about 5 square inches rounded part near testicles have this problem. (My physiology is poor, so hopefully am able to answer it)