The most common symptom of kennel cough is a dry hacking cough that may sound like honking, according to petMD. Retching and a watery nasal discharge may also be present. In most cases, there is no change in the dog's activity level or appetite.
In severe cases, symptoms worsen, and the dog may develop a fever, become lethargic, lose its appetite and develop pneumonia, explains petMD. Unvaccinated puppies and young dogs, as well as dogs whose immune systems are compromised, are at the highest risk of developing severe cases of kennel cough.
Also known as tracheobronchitis and bordetella, kennel cough is a contagious canine respiratory disease that causes the trachea and bronchi to become inflamed. It spreads through the air or via contact with contaminated surfaces, advises the ASPCA. The symptoms often dissipate within three weeks without treatment. It is helpful to isolate the dog from cigarette smoke or other noxious fumes and to use humidification to provide relief from symptoms. A veterinarian may prescribe a cough suppressant or antimicrobial.
Very young puppies, elderly dogs and dogs with compromised immune systems may take as long as six weeks to recover from kennel cough, notes the ASPCA. Dogs sometimes remain infectious for long periods of time after symptoms resolve.