The list is long of things that this could be, and it's important to have a doctor take a look at this in person, along with gathering a bit of your medical history in order to tell you for sure what the cause is. For now, just keep it clean- you can try to change laundry detergents and avoid fragrances to see if that might be causing some irritation. Otherwise, give the doctor a call to see when they can fit you in.