What are some causes of shaking and shivering in small dogs?

Small dogs shake and shiver when they are excited, nauseous, elderly, in pain or if exposed to toxins, advises WebMD, in its Healthy Pets, Healthy Dogs section. Medical conditions, such as distemper and generalized tremor syndrome, cause tremors or shaking in small dogs.

Excitement leads to shaking in some dogs, adds WebMD. Nausea is a common cause of shaking and shivering. Elderly dogs tremble, especially in their back legs. Dogs must be evaluated by a veterinarian to determine if the tremors are caused by pain.

Exposure to toxins and poisons causes shaking and tremors. Xylitol, chocolate and nicotine are three common poisonous items that cause tremors when ingested by dogs.