Discolored, slightly dry strip of skin around anus/down butt crack

Patient: Discolored, slightly dry strip of skin around anus/down butt crack. There never was any discoloration in this area before but for the past few months a strip of slightly darker skin has developed.. It’s almost yellow in color, and very embarrassing. Looking to see if this is normal or if there is a way to diminish the appearance of this “rash”. It’s not itchy and I’m thinking it may be food I’ve been eating.. Any help would be much appreciated

Doctor: