Coco has alot of Alergies and when the Pollen starts cming out she sneezes alot. She also gets Rashes. When she was 9 she had a bad reaction to something and her fur came out in Clumps. Your Cat might have Allergies you can talk to the Vet.
However, cats can't breathe through their mouths, just through their noses, so a cold can be very serious. See this recent thread from someone who fostered a cat with URI that got her other cats sick, one of whom was fine, the other of whom had a protracted serious illness.