This is the most common symptom a dog will experience when suffering from asthma. Dogs with asthma will commonly have "asthma-attacks", in which they will begin to cough, wheeze or struggle to breathe. While this is the defining symptom for a dog suffering from asthma, some pet owners may mistake an asthma attack for an episode in which a dog is trying to cough up a hairball or swallowed object.
In any case, an episode of incessant coughing is always cause for concern, and should be reason enough to seek veterinary attention as soon as possible.
Some dogs that are being affected by asthma will show a visible change in behavior. This behavioral change usually manifests as a loss of interest in normal everyday activities. While lethargic behavior is not always a defining symptom of dogs suffering from asthma, it is still usually cause for concern.
In some cases, a dog with asthma will display a lack of interest in anything food-related. Dogs with asthma may eat less food, or ignore food altogether. If this symptom persists over an extended period of time, secondary symptoms may occur. This includes malnutrition, hair loss, weight loss, and complete lack of energy.
In advanced cases of asthma in dogs, a dog may begin to experience severe respiratory distress. This may include a host of other symptoms such as open-mouth breathing, severe coughing, wheezing, and in some cases, complete loss of consciousness. Though severe respiratory distress is relatively uncommon in dogs with asthma, it is still possible that a dog with asthma will experience this symptom.
The occurrence of severe respiratory distress is classified as an emergency situation, and it is extremely important to seek veterinary care immediately.
If your dog has a purple tinge to their mouth, tongue or gums, this could be a symptom of severe respiratory distress. This symptom could signify that your dog is being affected by asthma. When a dog is having trouble breathing, this results in a lower blood oxygen level. When this occurs, blood cells begin to appear purple or bluish in color (as a result of the loss of oxygen).
This is a very dangerous situation, and means that your dog is not inhaling enough oxygen to keep their bodily systems functioning at a normal level. If this symptom occurs, it is extremely important to bring your dog to the nearest emergency veterinary facility.