Reverse sneezing (also called backwards sneezing or inspiratory paroxysmal respiration) is a phenomenon observed in dogs, particularly in those with brachycephalic skulls. It is a fairly common respiratory event in dogs, but is rarely seen in cats. Its exact cause is unknown but may be due to nasal, pharyngeal, or sinus irritation (such as an allergy), the dog's attempt to remove mucus, or from over-excitement due to present activity. It is characterized by rapid and repeated forced inhalation through the nose, accompanied by snorting or gagging sounds. Though it may be distressing to the animal, it is not harmful. Most dogs are completely normal before and after episodes. In addition, most dogs will have repeat episodes of reverse sneezing throughout their lives.According to Holly Freeman, DVM, "During a reverse sneeze, the dog will make rapid and long inspirations, stand still, and extend his head (and neck). A loud snorting sound is produced...".Reverse sneezing also commonly occurs while the dog is startled from a deep sleep or immediately following a long nap. Other dogs may experience it following play, exercise, or meals. However, episodes are typically random. Though smaller dogs seem slightly more susceptible to reverse sneezing, any dog can develop it, regardless of size. It can also happen by breathing in dust.Differential diagnoses include tracheal collapse.A common remedy is to pinch the dog's nose and scratch its throat. Lightly blowing in its face may also help. The dog will swallow a couple of times and then stop the reverse sneezing. Additionally, calming the dog down by rubbing its sides or back also helps to end the episode more quickly. While most dogs do not require medication, antihistamines and steroids may help if the problem is serious, chronic, and allergy related.