Kennel cough
Symptoms can include a harsh, dry coughing, retching, sneezing, snorting (noise made with the nose), gagging or vomiting in response to light pressing of the trachea or after excitement or exercise.  The symptoms are caused by the inflammation of the airways.  It can increase after excitement or exercise because of the quick breathing that takes place which causes the nerves of airway to become more stimulated.  A fever is not always present.  The disease can last 10–20 days and can come back when the dog is put into a stressful situation which puts stress on the dog's immune system.  Medical diagnosis is made by seeing these symptoms, having a history of exposure is also helpful but not always found as kennel cough is easily spread through contact with the ground, toys, sidewalks, dog parks.