Thanks for using this forum. By the description of your clinical symptoms this seems to be some sought of infection perhaps of fungal origin, as these tend to spread fast and be more itchy. However as you have already booked with the specialist, he/she can determine its cause by taking even a small skin biopsy
. Usually for such conditions antifungal creams along with antifungal shampoos are usually prescribed. Feel free to write in. Regards.