Why is my dog shaking? Causes and when it's an emergency

Seeing your dog tremble for no obvious reason is unsettling. Sometimes the explanation is as simple as a chilly morning or excitement about the leash coming off the hook. Other times, shaking is the first sign of pain, poisoning or a blood sugar crash that needs immediate care. Figuring out why your dog is shaking comes down to context and whatever other symptoms show up alongside it.

This guide walks you through how to tell shaking from a seizure, the harmless causes and the ones to watch, a quick reference table by situation and what to do, step by step, while you decide whether it's an emergency.

Shaking, shivering or seizure: how to tell the difference

Before you look for a cause, notice how your dog is shaking. A dog that trembles while alert and responsive is very different from one having a seizure and losing contact with you.

If your dog wakes up when you say its name and acts normally, it was most likely dreaming: dogs have REM sleep too. If you suspect a seizure, keep your hands away from its mouth, move objects it could hit and time how long it lasts.

Harmless or normal causes

Cold

This is the most obvious cause and the most common one in small, short-coated or lean dogs (Chihuahuas, whippets, greyhounds), puppies and seniors. The shivering stops within minutes once your dog is wrapped up or back indoors. If it doesn't stop, or your dog seems sluggish and clumsy, it could be hypothermia. Our winter dog care tips cover coats and safe temperatures.

Fear, stress and anxiety

Fireworks, thunderstorms, the vet's office or a car ride. You'll usually see a tucked tail, ears pinned back, panting, yawning, lip licking or attempts to hide. If your dog trembles every time there's a loud noise, here's how to help a dog afraid of fireworks and thunder.

Excitement

Plenty of dogs tremble with pure anticipation when they see the leash, when you get home or while waiting for a treat. It fades as soon as they settle and there are no other symptoms.

Old age and muscle weakness

Older dogs often have trembling back legs when standing or getting up. Muscle loss, arthritis or pain are the usual reasons, so it's worth a checkup even if it isn't urgent. Our guide to senior dog care shows how to adapt their routine.

Medical causes to watch for

Pain

Shaking is a more common sign of pain than most people think, especially with back pain (such as a slipped disc) and belly pain. Look for a hunched posture, panting at rest, reluctance to move or climb stairs and whimpering when touched. Brush up on the signs your dog is in pain to catch the subtle ones.

Nausea

A nauseated dog may tremble while drooling, licking its lips, swallowing repeatedly or hunting for grass. It's common with car sickness and right before vomiting.

Fever

Shivering can be a sign of fever. A dog's normal rectal temperature is 100.5–102.5 °F (38–39.2 °C); if you've never taken it, here's how to tell if your dog has a fever.

Low blood sugar in toy breeds and puppies

Toy breed puppies (Chihuahuas, Yorkshire terriers, Pomeranians, toy poodles) have very small energy reserves. If they skip a meal, get chilled, get stressed or have vomiting or diarrhea, their blood sugar can drop within hours. Signs include weakness, trembling, wobbling, a glassy stare, confusion and, in severe cases, seizures or collapse. It can also happen in diabetic dogs on treatment.

This is an emergency. If the puppy is conscious and able to swallow, rubbing a little honey or corn syrup on the gums is a standard first-aid step on the way to the vet. Never use anything sugar-free (xylitol is toxic to dogs), and never put anything in the mouth of an unconscious dog.

Poisoning

Many toxins cause muscle tremors, often along with vomiting, drooling, agitation or poor coordination. Common culprits include:

• Chocolate, coffee and other sources of caffeine.
• Xylitol (sugar-free gum and other "sugar-free" products), which causes a sudden blood sugar crash.
• Moldy food, garbage or compost, because of toxins produced by molds.
• Snail and slug bait and some insecticides.
• Marijuana and human medications (antidepressants and ADHD stimulants, among others).

If you suspect poisoning, call your vet, an emergency clinic or a pet poison hotline such as the ASPCA Animal Poison Control Center right away, and don't make your dog vomit unless a vet tells you to. See dog poisoning symptoms for more.

Generalized tremor syndrome

Also known as "little white shaker syndrome," because it was first described in small white dogs like Maltese and West Highland white terriers, although dogs of any breed or color can get it. It usually appears in young or young adult dogs and causes whole-body tremors that get worse with excitement and ease at rest, while the dog stays alert. Most dogs respond well to the treatment a vet prescribes.

Other causes

• Eclampsia (milk fever): a calcium drop in nursing mothers, typically in the first weeks after giving birth and more often in small breeds. Restlessness, panting, tremors and stiffness. It's an emergency.
• Distemper: can leave unvaccinated dogs with rhythmic muscle twitching.
• Kidney, liver or hormonal disease, such as Addison's disease.
• Neurological problems and head injuries.

Quick reference: what shaking may mean in each situation

What to do if your dog is shaking

1. Check whether your dog responds to its name and whether the shaking is in one area or the whole body.
2. Move your dog somewhere quiet and warm, and wrap it in a blanket if it's cold. Talk calmly.
3. Look at the gums: they should be pink and moist. If they're pale, bluish or bright red, head to the emergency vet.
4. Take your dog's temperature if you know how and have a digital thermometer.
5. Search the house and yard for anything your dog may have eaten: wrappers, pill bottles, trash, bait. Bring whatever you find to the vet.
6. Film the shaking and note when it started and how long it lasts.
7. Don't give human medications, and don't try to make your dog vomit on your own.

If the shaking stops within minutes once your dog is warm or calm and it's back to normal, keep an eye on it. If it keeps happening without explanation or won't stop, book a vet visit. This guide can't replace an exam: telling similar causes apart often takes hands-on assessment and tests.

How to prevent avoidable shaking

• Use a coat on small, short-coated or senior dogs on cold walks, and dry them thoroughly after baths.
• Split meals for toy breed puppies into 3–4 feedings a day and don't let them skip meals.
• Keep out of reach chocolate, anything with xylitol, medications, bait and insecticides, and use a dog-proof trash can.
• Work on fear of noises and vet visits ahead of time, not on the day.
• Keep vaccines current to protect against distemper.
• Schedule checkups at least once a year, and every six months for seniors.

Frequently asked questions

Is it normal for a Chihuahua to shake all the time?

Chihuahuas and other toy breeds tremble easily: they have little body mass, lose heat quickly and many react strongly to their surroundings. If the shaking stops when your dog is warm or calm, and it's eating, playing and moving normally, it's usually not a problem. If it's new, doesn't stop or comes with weakness or a poor appetite, call your vet, especially with a puppy.

Why is my dog shaking after vaccines?

After a vaccine, some dogs are tired, run a slight fever or feel sore at the injection site for a day or two, which can cause some shivering. That's a mild reaction. Call your vet right away if you see facial swelling, hives, vomiting, diarrhea or trouble breathing, because these can signal an allergic reaction that needs treatment.

Why are my old dog's back legs shaking?

The most common reasons are age-related muscle loss, arthritis in the hips or knees and back pain. Sometimes it's a benign age-related tremor, but that's only a safe conclusion once pain and other problems have been ruled out. A checkup with an orthopedic and neurological exam opens the door to pain management and exercises that help preserve muscle.

Why is my dog shaking and panting?

Shaking plus panting is common with intense fear, like during a thunderstorm, but it also shows up with pain, fever, nausea, some poisonings and heatstroke. If there's no obvious reason for fear, or the panting continues while your dog is resting in a cool spot, call your vet the same day.

Why does my dog shake after a bath?

Usually it's cold, since a wet coat loses heat fast, especially in small dogs, or stress from the bath itself. Towel your dog off well and, if it tolerates it, finish with a dryer on a warm, not hot, setting in a draft-free room. If the shaking continues well after your dog is dry and warm, look for another cause.

Sources

• Merck Veterinary Manual: tremors, generalized tremor syndrome and hypoglycemia in dogs.
• ASPCA Animal Poison Control Center: household toxins that cause tremors in dogs.
• VCA Animal Hospitals: hypoglycemia in toy breed puppies.
• American Kennel Club (AKC): why dogs shake.