For millions of pet owners, cat allergies can turn affection into frustration. Doctors explain that it’s not fur that causes the reaction, but a protein called Fel d 1, found in cat saliva and skin.

Which low-protein cat food is best? Switching your cat to a low-protein diet isn’t a matter of preference — it’s a matter of health. Cats are obligate carnivores, meaning they can’t get the nutrients ...