Kennel cough is very contagious but not dangerous. You might want to mention his condition to any facility he's been in recently. They can do what they want with the information.
6 Canine Kennel Cough Recovery Tips
Canine kennel cough happens when dogs are exposed to germs from other dogs in enclosed spaces. A vaccination is available, but if your dog happens to catch this illness, follow the tips below to help your dog recover:
Make sure you have proper ventilation in your home. Provide your dog with plenty of clean, fresh air. Exposure to smoke from fireplaces or cigarettes and fumes from household chemicals will make recovery tougher.
Cough syrup is an acceptable way to treat canine kennel cough. Vets recommend Robitussin, or similar cough suppressants, given according to the dog's size.
Soothe your dog's air passages and throat by adding moisture and humidity into the air. You can use a humidifier, vaporizer or take your dog into the bathroom when you are showering to expose him to the steam.
Help drain your dog's airways by taking him on a slow and relaxing walk. The movement will help loosen up his air passages. Don't overwork him as this can increase his coughing.
Canine kennel cough is highly contagious so keep your dog away from her furry friends until the infection subsides. Remember: Some facilities require proof of immunization for canine kennel cough before your dog is allowed to lodge here.
A typical recovery period from kennel cough is 7 to 10 days, during which time you should provide as much comfort as possible for your pet. If your dog does not respond to such treatments and develops a fever or loss of appetite, take him to the vet. In some cases kennel cough will lead to pneumonia.
Poor Diamond! Hope he's feeling better soon.