Hi ! It would be better if you consult in person as the description you have given is vague.From what you have described it could be a fungal infection,but it is best to see it in person.Till you consult,you can try using clotrimazole dusting powder twice a day.
Next Steps
Do not share your towels and soaps . Consult a dermatologist in person as early as possible.
Health Tips
Do not use any over the counter medications/ointments .It could aggravate the itching more!