6 Signs of Illness in Your Pet (cont.)

Coughing

"Coughing, especially if it's persistent, is one of those pet symptoms that need to be evaluated," Sawchuk says. Chronic coughing may be related to heart disease, heartworms, or lung diseases.

Or a dog may have kennel cough, an infectious tracheobronchitis that causes a harsh, hacking cough. For most dogs, kennel cough is mild -- a nuisance that goes away within two weeks, Sawchuk says. But for puppies, kennel cough can progress to fatal pneumonia.

Also, kennel cough may be more serious for dog breeds with pushed-in faces, such as boxers, bulldogs, pugs, and Boston terriers, Sawchuk says. Their unusual head anatomy can compromise their respiratory systems and create breathing difficulties.

If a puppy or dog with kennel cough develops more serious symptoms, such as fever, nasal discharge, loss of appetite, lethargy, or a productive cough, it may be getting pneumonia.

While any lasting cough should come to a veterinarian's attention, owners can also take protective measures by vaccinating their dogs against some of the organisms that cause kennel cough.

Owners should also tell a vet about persistent sneezing or discharge from the eyes, ears or nose. Also, "any animal that has difficulty breathing, rapid breathing, or choking -- those are all reasons to seek veterinary help," Randolph says.