Most of the time, excessive sneezing in cats and dogs is a sign of an irritation, inflammation or infection of the upper respiratory system (involving the nasal passages and sinuses).
Allergy in cats and dogs more frequently affects the skin or digestive tract. Individuals allergic to seasonal pollens, for example, are more likely to feel very itchy and scratch or chew at body surfaces. Food hypersensitivity occurs in pets and can be difficult to distinguish from a long list of ailments that cause itchiness and coat problems. It can also be present as diarrhea and other nonspecific signs of gastrointestinal upset. Allergy to medication can trigger skin, digestive and respiratory problems.
Respiratory signs that are so commonly related to allergy in people do occur in pets. Allergy-induced sneezing in dogs is associated with seasonal pollen although the skin symptoms usually predominate. Feline asthma is characterized by wheezing and moist coughing. It is thought to be an allergic phenomenon, but feline asthma may also be triggered by emotional stress such as reaction to separation. If your pet is sneezing, try to record how many times during twelve or twenty-four hour period. Is there any nasal discharge and if so, is it cloudy or clear? Do the eyes seem affected, too? Is there any change in appetite or level of activity? If sneezing is complicated by any other signs of discomfort or disease or if the sneezing lasts for more than two days, consult your pet’s doctor.