sometimes I have itches in same area too. I exfoliate area, disinfect and moisturise with vicks. usually it goes away and I dont feel like itching due to the menthol. so I conclude that maybe for me since its a bit harder to reach and I always apply stretchmark creams; area has buildup that bacteria feed on. but always better to consult doctor.
I have the same problem and I tried applying bio oil generously and now I don’t feel the itch anymore..
You might wanna visit a dermatologist for that!