The most common kennel cough symptom is a retching and loud hacking cough. Besides, there are certain other symptoms of kennel cough as well, but they are not so prevalent. They are sneezing, discharge from their eyes, and have runny noses. In some extreme cases, kennel cough can also result in lethargy, fever, loss of appetite, and even anxiety and depression. These symptoms are more visible if the disease is left untreated for a long time.