Any sudden change in your dog’s breathing could be serious. A dog in a true emergency will often appear distressed; you can tell by the expression on their face and you may see more of the whites of their eyes.
If their gums are turning blue, brick red, or pale/white then you definitely want to be headed to an emergency hospital.
One notable exception to this is ‘reverse sneezing syndrome’. This is actually a harmless condition that can appear quite dramatic if you don’t know what it looks like. It is worth checking out some videos of reverse sneezing online to make yourself familiar with the appearance.
A ‘reverse sneeze’ usually occurs in small breed dogs and may be associated with allergies. It looks like a very forceful inhale through the nose, and is often quite loud. If you’re unsure if what your dog is doing is a reverse sneeze, it is always best to call your vet to make sure.
While less dramatic, any dogs with mild but chronic breathing issues (lasting more than a few days), should get checked out by their veterinarian. This is especially important if you notice that their overall appetite or energy are affected.