I would think it was possible for one ear to have a sensitivity to the earring and not the other. I had to give up my earrings years ago as I have a terrible allergy to wearing them, even the 18k gold type.They would become infected and pus would ooze out. I have so many allergies I don't even try new things any more. I have a watch I wear all the time which has a stainless steel back which breaks my skin out. I have to coat the back with clear finger nail polish in order to wear it!!!!!!