Suggest Treatment For Infection On Outer Edge Of Ear

HI , My mother is 88 years old and she has an infection on the outer edge of her ear that doesn t want to heal. The outer edge of her ear has split open and the ear is really sore to the touch. We have tried all types of ointments but the ear doesn t heal,this has been going on about a year. The doctor has seen her and wants her to see a specialist. What could this be, I am going to make an appointment for her what can we try to heal the ear. Thanks.