Dogs often shake if they are cold or wet, notes Dog Symptoms Cure. Smaller dog breeds are also known for shaking. It can be a serious problem if the dog shakes for an extended period of time, in which case a veterinarian should be consulted.
Dog Symptoms Cure states that more serious symptoms of shaking include fever and ear mites. A dog might shake his head due to an ear infection as well. Web MD discusses the issue of doggy ear infections, with symptoms such as frequent shaking of the head or loss in equilibrium.
Pet Wave notes a more serious condition called Addison's Disease. This disease degrades most of a dog's adrenal cortex. The condition affects dogs in different ways, but a few common symptoms are seizures and shock. The Daily Puppy highlights chronic renal failure and neurological problems as other potential causes of irregular shaking.
Dogs can also shake during stressful situations, according to 4 Paws University. A dog can shake during anxiety-prone circumstances, such as visits to the veterinarian or thunderous lightning storms. The Daily Puppies also explains that dogs manifest their fears and uncertainty in physical ways. Shaking or trembling is a general sign of nervousness and apprehension. The reason for shaking can stem from happiness as well, especially if an owner is gone for a long period of time and then returns.