Coughing

• Coughing is a reflex that the body uses to clear secretions or irritants from the throat or wind pipe. These secretions affect the respiratory system and can make it difficult for your dog to breathe. If your dog's coughing persists for longer than a few weeks, have your dog seen by a veterinarian. Using a harness instead of a leash may help lessen your dog's reflex to cough.
  
  

Kennel Cough

• Kennel cough is spread through dogs in close quarters, such as a kennel setting. According to thedogdaily.com, kennel cough is a mix of bacteria and viruses in a canine's airway. If kennel cough is treated with antibiotics, it should go away in one to two weeks. If your dog is around other animals, he should be confined while he is sick so he won't spread the disease to the other animals.
  
  

Heart Disease

• Coughing with fluid in the lungs can be a symptom of heart disease. Thedogdaily.com states that a dog who is suffering from fluid in the lungs may cough more at night than during the day. Enlargement of the heart due to heart disease may also cause coughing. Breeds such as Cocker Spaniels, Dobermans, Boxers and smaller dogs are more likely to develop heart disease and coughing.
  
  

Parasites

• Heartworms and roundworms may cause your dog to cough. These worms can move into the windpipe, causing sudden coughing, according to canismajor.com. Your veterinarian can treat heartworms with dewormer medications and preventatives, depending on the severity of the worm infestation. If they are not treated early enough, heartworms can be fatal.
  
  Roundworms can cause blockage in the intestines and decrease nutrient absorption in the stomach. They are only fatal if the dog is already weakened from a previous medical problem. Your veterinarian can provide anti-worming medications to rid your dog of roundworms.
  
  

Other Causes

• Other causes of sudden coughing in dogs may include: fungal infections, foreign objects caught in the dog's windpipe, chronic bronchitis, lung cancer and influenza, a highly contagious respiratory infection.
  
  Distemper can also cause coughing in dogs. Distemper is a highly contagious viral disease that can be fatal in young puppies and debilitating in older dogs. All dogs should be vaccinated against distemper, according to thedogdaily.com. Puppies should be vaccinated early against distemper and kept away from strange dogs to prevent contact with distemper.