Frequent or ongoing coughing and gagging by your dog may be a sign of any of several conditions, ranging from a simple throat irritation through to a serious illness such as heartworm or heart disease. Unless the symptoms stop within a short period, the dog may need veterinary treatment. Watch him carefully for signs of distress, difficulty in breathing, lethargy or seizures, as these could indicate a medical emergency.
Offer the dog water to clear any dust in the throat, or a piece of bread to push down any minor obstructions. Open the dog’s mouth and look into his throat to see if you can identify any obvious blockage. If so, do not try to remove the blockage; take the dog to your veterinarian immediately, as removal may cause damage to the trachea. If no blockage is present, evaluate whether the dog needs immediate veterinary help, and watch him closely for signs of improvement or worsening.
Dogs that have not been vaccinated against bordetella run the risk of developing infectious canine tracheobronchitis, also known as kennel cough, after contact with infected dogs. An infected dog produces a dry, hacking cough that may be accompanied by retching or gagging. The cough might have a honking sound. Dogs sometimes develop a watery nasal discharge. (Refs 2) Other causes of canine tracheobronchitis include the common parainfluenza virus, which can result in the dog coughing up blood. Kennel cough is treated using an anti-inflammatory agent; if your veterinarian suspects secondary infection, she may prescribe antibiotics.
Dogs living in warm, tropical climates are particularly susceptible to infection by the heartworm organism, which enters the body by transmitting larvae through mosquito bites. The larvae develop into worms that cause enlarged arteries in the heart. Dogs with heartworm disease may cough occasionally, or they may develop a chronic cough. Your vet will prescribe an adulticide to kill heartworms, or, in some cases, surgery is necessary.
Heart diseases such as dilated cardiomyopathy and chronic valvular disease both include coughing as a symptom. Certain giant breeds are predisposed to cardiomyopathy, which is caused by enlargement of parts of the heart. Toy breeds are prone to chronic valvular disease, which affects the performance of the valves, causing reduced efficiency. Coughing occurs because of pressure on the airways or lung congestion, which could lead to congestive heart failure. If it occurs mainly at night or after exercise, or is accompanied by rapid breathing or coughing up blood, you should have your dog examined by a veterinarian immediately.
A variety of less common medical conditions can cause symptoms of coughing and gagging in dogs. These include anatomic airway malfunctions, allergic inflammation or chronic pulmonary obstructive disease, which is a long-term inflammation of the trachea. A dog who has suffered a tracheal collapse also displays symptoms of coughing. This occurs mainly in elderly or overweight dogs and can be caused by the dog pulling against his collar. Several toy breeds are predisposed for collapsed tracheas.