Why does a dog shake?
A tremor is a rhythmic, involuntary movement of one part of the body or of the whole body. The causes fall into three groups: normal reactions (cold, emotion), signs of another problem (pain, nausea, weakness) and diseases that directly affect the nervous system, from poisoning to metabolic and neurological diseases.
Cold, fear, excitement
Small, short-coated dogs and older dogs shake easily from the cold. Fear, stress (thunderstorms, fireworks, the trip to the vet) and excitement before a walk can also cause shaking. It stops once the dog warms up or calms down.
Pain and nausea
A dog that shakes while standing still with its back hunched, and avoids climbing or jumping, may be in pain, for example in the back or neck. Shaking can be the first sign of a slipped disc (intervertebral disc disease). Nausea before vomiting is also often accompanied by shaking, drooling and lip-licking.
Back legs in older dogs
In older dogs, shaking back legs often go hand in hand with loss of muscle mass: the weakened muscles tire while the dog is standing. The same picture can, however, come from arthritis or a disease of the spine. If your dog also becomes unsteady, crosses its legs or scuffs its nails on the floor, it needs to be examined.
Poisoning: the most common cause of whole-body tremors
In a study of 198 dogs with tremors affecting the whole body, 46% had been poisoned. The most common causes were mycotoxins (from mouldy food, rubbish or compost) and slug pellets containing metaldehyde, followed by parasite treatments from the avermectin group, cannabis, chocolate, chewing gum or sweets containing xylitol, and recreational drugs. The tremors start suddenly, affect both sides of the body equally, and often come with drooling, dilated pupils, agitation or strange behaviour.
“Shaker” syndrome (idiopathic generalised tremor syndrome)
This was the second most common cause in the same study: 25% of the dogs. It is considered an immune-mediated disease, also known as little white shaker syndrome, because it was first described in small white breeds such as the Maltese, the West Highland White Terrier and the Bichon. It does, however, occur in dogs of any colour, usually young (a median age of 2 years in the study) and small or medium-sized.
The tremor is fine, affects the whole body or mainly the head, gets worse with excitement and exercise, and eases at rest and during sleep. The dog stays conscious and alert. The diagnosis is made after poisoning and metabolic diseases have been ruled out. The response to the immunosuppressive treatment chosen by the vet is usually good: in one study, 80% of dogs responded within 3 days, and in the recent study almost all the dogs followed up improved.
Low blood sugar (hypoglycaemia)
A drop in blood sugar causes weakness, disorientation and shaking, and can progress to seizures and collapse. It occurs in toy-breed puppies that are not fed enough, in diabetic dogs after too much insulin, after eating xylitol and, in middle-aged or older dogs, with a tumour of the pancreas called an insulinoma. It is an emergency.
Low calcium (hypocalcaemia, eclampsia)
In nursing bitches, especially small ones with large litters, calcium can drop suddenly, most often 2-3 weeks after giving birth. This is eclampsia, sometimes called milk fever. The first signs are panting and restlessness, followed by tremors, stiffness and seizures. Eclampsia is life-threatening: go to an emergency clinic straight away.
Tremor or focal epileptic seizure?
The main difference is the rhythm and the context: a tremor is a regular oscillation while the dog is conscious, and it stops during sleep; a focal seizure is a short episode that follows the same pattern every time and can turn into a generalised seizure.
| Tremor | Focal seizure | |
|---|---|---|
| What it looks like | A fine, regular to-and-fro oscillation | Twitching of the face, rhythmic movements of the head or one leg, rhythmic blinking |
| Consciousness | Preserved; the dog responds when you call it | May be preserved or slightly altered; sometimes progresses to loss of consciousness |
| Duration | Minutes, hours or days | Usually seconds to a few minutes |
| Other signs | Gets worse with excitement or exercise | Drooling, dilated pupils, confusion after the episode |
Borderline cases cannot be told apart from a description alone. A video of the episode helps a great deal, and sometimes only an EEG can show whether the brain's electrical activity is that of a seizure. You will find more about focal seizures in the article on types of epileptic seizure.
A neurological consultation tells you where the problem comes from and what to do next.
When is shaking an emergency?
| Probably harmless | See your vet | Emergency |
|---|---|---|
| Shakes in the cold and stops once warm | The shaking comes back every day, with no clear cause | Sudden whole-body shaking after possibly eating something toxic |
| Shakes during thunderstorms, fireworks or at the vet, and calms down afterwards | Shakes and will not eat, stands hunched or avoids moving | Shaking with drooling, vomiting, dilated pupils or agitation |
| Shakes with excitement before a walk | An older dog's back legs shake and it starts to wobble | A nursing bitch that is panting, restless and shaking |
| Brief twitches during sleep, wakes up normally | A young, small dog with a fine tremor for several days | A small puppy or a diabetic dog that is weak and disorientated |
| Short, repeated episodes that follow the same pattern | The shaking turns into convulsions or loss of consciousness |
Before the consultation, write down when the shaking started, whether it is constant or comes in episodes, which parts of the body shake, whether it stops during sleep or when your dog is distracted, and whether it could have got hold of spoiled food, slug pellets or bait, or medicines. Film a few episodes with your dog's whole body in the frame and, while filming, try calling it by name: its reaction says a lot about its level of consciousness. Also bring a list of the treatments and parasite products used recently.
In an emergency, also outside opening hours, send a WhatsApp message or call 0745 145 033; the emergency consultation, outside opening hours, costs 500 lei. If a seizure lasts longer than 5 minutes, or you cannot reach the practice, go straight to the nearest emergency vet clinic that is open now. For shaking that persists or keeps coming back, once emergencies have been ruled out, a neurological consultation will clarify whether it is a problem of the nervous system. For other signs, see the guide to neurological symptoms in dogs.
A neurological consultation tells you where the problem comes from and what to do next.
Frequently asked questions
Why are my old dog's back legs shaking?
In older dogs, shaking back legs often go hand in hand with loss of muscle mass: weakened muscles tire quickly, especially while standing or after exercise. It can, however, also point to joint pain or a spinal problem, so it is worth having it examined, particularly if it gets worse or your dog also becomes unsteady on its feet.
My dog shakes in its sleep. Is it a seizure?
Usually not. Brief twitches during sleep, with paws that seem to be “running”, are normal, and the dog wakes up straight away when you call it. A seizure does not stop when you call or touch your dog and is often followed by a period of confusion. If you are not sure, film the episode.
My dog is shaking and not eating. What does that mean?
This combination usually suggests pain, nausea or a general illness rather than a simple reaction to the cold. Call your vet the same day, and if repeated vomiting, weakness or heavy drooling appear, go to an emergency clinic.
Can I give my dog something to calm it down at home?
Not without your vet's agreement. Sedatives and human medicines can be dangerous for dogs and can mask the signs of poisoning or illness. Keep your dog warm and quiet, and call the vet.
Sources
- Liatis T, Bhatti SFM, De Decker S 2025, Generalized tremors in dogs: 198 cases (2003-2023), Journal of Veterinary Internal Medicine
- Bagley RS et al. 1997, Generalized tremors in dogs: 24 cases (1984-1995), JAVMA
- Cerda-Gonzalez S. et al. 2021, ECVN consensus statement on canine dyskinesia: terminology and classification, Journal of Veterinary Internal Medicine
- Berendt M. et al. 2015, International veterinary epilepsy task force consensus report on epilepsy definition, classification and terminology in companion animals, BMC Veterinary Research
- VCA Animal Hospitals, Shaker Syndrome in Dogs
- VCA Animal Hospitals, Testing for Low Blood Sugar
- MSD Veterinary Manual, Eclampsia in Small Animals
- American Kennel Club, Why Is My Dog Shaking?
This article is for information only and does not replace a veterinary consultation.