If your dog shakes, shivers or trembles uncontrollably, he could be suffering from fear issues or a serious medical disorder. Observe your dog’s other physical behaviors, taking into consideration his surroundings and the temperature. Make note of anything he may recently have ingested. Seek veterinary medical attention as soon as possible to ensure you're addressing the root of the shivering problem.
Hypothermia, Heat Stroke, Fever
Dogs shiver when they become hypothermic due to extremely low temperatures. They may also tremble and shake if they are overheated. This is generally accompanied by labored breathing, a bright red tongue and pale gums as well as vomiting or diarrhea. Your dog may shiver if he has a fever due to infection or other illness. According to Web MD, dogs running a fever over 106 degrees Fahrenheit need immediate veterinary attention; fevers of 103 merit a call to the vet. You can help cool a dog whose body temperature is 105 or higher by applying cool water around the ears and feet and using a fan on the damp fur. WebMD says you should monitor your dog’s rectal temperature as you do this and stop the cooling procedure when the dog's rectal temperature reaches 103 degrees Fahrenheit.
If your dog gets into any type of chocolate, tobacco product or toxic chemical in or around your home such as lawn fertilizer, insecticide or even some types of plants or gardening mulch, it could create a reaction that manifests itself in shaking, trembling or shivering. This may be accompanied by convulsions, vomiting, diarrhea or even loss of consciousness. Seek immediate medical attention and bring a sample of whatever your dog ingested to the vet if possible.
Fear, Pain, Excitement
Your dog may shiver due to fright or excitement, an occurrence common in smaller or excitable dog breeds. Some dogs tremble when they encounter other animals, or if they have a form of anxiety in which meeting other people makes them overly anxious. Loud noises ranging from thunderstorms to vacuum cleaners and power tools can also frighten dogs to a point of shivering. Shivering can also be a sign your dog is in pain. This could be associated with an injury, an illness or an attack or bite from another animal or poisonous insect or snake. As with other causes of shivering, you should start your moderation of the problem with a visit to the vet, who can refer you if necessary to a behaviorist.
Underlying Medical Conditions
Uncontrollable shivering is a sign associated with numerous canine medical conditions, such as distemper, kidney disease or seizure disorders. If you notice a sudden onset of shivering, if shivering does not subside when your pup is warm or calm, or if you notice other unusual physical or behavioral issues, seek a medical evaluation. Your vet will likely conduct a physical exam, ask questions and run blood tests to determine the root cause of the shivering to make a diagnosis.