Pets can also have food allergies, but they're less common than inhalant allergies, Dr. Boyanowski says. For instance, only about 10 percent of allergic dogs exhibit true food allergies.
Unlike people, it's rare for cats and dogs to manifest allergies by sniffling, sneezing or coughing. A coughing cat, however, may have allergy-related asthma.
Allergies can be genetic, but whether a pet develops allergies depends on the convergence of three events: genetic predisposition, exposure to an allergen, and a reaction to that allergen. "If they are not genetically predisposed or they don't have an exposure or haven't triggered a reaction, they could theoretically on a blood test or skin test react as an allergic patient but not be displaying symptoms," Dr. Boyanowski says.