Why Is My Dog Flinching All Of A Sudden?


It’s something no loving pet owner ever wants to see. 

Your dog flinching away from your hand, tail tucked between his leg, fear in his eyes – what does it even mean? 

A dog could be flinching all of a sudden for a variety of reasons and it’s got nothing to do with you or something you did. 

Let us examine some of the most common reasons this might be happening and see what you can do to help your dog become his old confident self again.

What is flinching?

Flinching is an instinctual reaction of fear, more common in shy or sensitive dogs. 

Or it might be a reaction caused by an old trauma, something bad that happened to him back when he was a puppy. 

Many abused dogs flinch when you raise your hand anywhere near them, but in this case it’s something the dog tends to do on a regular basis.

Now, if your dog never displayed such behavior before, when he starts flinching all of a sudden you need to look for the cause elsewhere. 

It’s not about an old trauma, it’s something that happened to the dog recently. 

For instance, the dog’s instinct to flinch when you just want to pet him might be related to some injury, an infection that causes him pain, vision or hearing problems, seizures or an incident that you did not witness and know nothing about.

There’s also the possibility that your dog’s sudden reaction is perfectly natural and has to do with his emotional development, the so-called puppy fear periods.

What are the two puppy fear periods?

According to experts, dogs go through two fear periods. 

One of them is when the puppy is quite young, roughly 8 – 11 weeks, while the second takes place when he gets in his teens, and this can be anywhere between 6 to 14 months.

First puppy fear period

As it happens, the first puppy fear period tends to coincide with the time most puppies meet their new families. 

At this age, puppies are starting to gain their independence from their mother as they are weaned right around eight weeks.  

They explore more and it is actually a good period for socialization. Yet, becoming independent also brings awareness of all the potential dangers out there.

Since it’s a delicate stage in the dog’s emotional development it’s best to avoid relocating the pup at this point and wait until he’s over it. 

Any traumatic incident taking place during this fear period might leave a powerful imprint affecting the dog for the rest of his life.

Second puppy fear period

If you have a young dog and he’s flinching all of a sudden it might just be that he’s entered his second puppy fear period. 

Now, a 12 months old dog is usually all grown up and you see him like an adult dog. 

He is not, deep down he is still a puppy and he is still learning about the world.

What you need to know is that this fear period doesn’t mean your dog will behave weirdly all the time, it’s not a continuous fear he’s experiencing. 

In most cases, the dog will have fear episodes, happening once in a while, for no apparent reason.

A dog going through this stage might become suddenly afraid of the trash can or the neighbor down the street he used to greet with a happy bark every day. 

You can not know what’s going on in his head.

If your dog is anywhere between 6 to 14 months, or even 18 months in some cases, his flinching all of a sudden might be caused by this fear stage and chances are he’ll outgrow it pretty soon.  

How can pain make a dog flinch all of a sudden

It can be quite distressing to see your dog flinch from your gentle approach in a reaction typical to children who’ve been through terrible abuse. 

The dog is not scared of you, however, he simply doesn’t want to be touched because he’s in pain. It can be anything from a wound to a strained muscle, a back injury or an infection.

If his back hurts it’s only natural for him to shy away from your touch. 

The dog might even give you an angry look at this point and in his confused little brain he might be actually angry at you because you’re the one in charge and you clearly aren’t doing anything to help.

The best way you can help is to take him to the vet and have him checked out. 

Obviously, you shouldn’t rush to the vet the first time your dog does this sort of sudden flinch as it might be anything, like an upset tummy that will go away the next day.

However, if you see your dog flinching more often or every time you go near him, you need to do something about it. 

If the dog allows it, try to examine him from head to tail and check for injuries, bites, ticks, or signs of infection.

If there’s an external cause to your dog’s sudden flinching, that is easily treatable and he’ll be back to his happy-go-lucky self.

Loss of senses can make the dog flinch all of a sudden

This is a problem affecting mostly senior pets who have to deal with declining health and a progressive weakening of their senses. 

Once again, it’s not your fault in any way, but the dog doesn’t know that, just as he doesn’t understand this age thing and nothing makes much sense to him.

When a dog’s vision is affected by cataracts, very common in elderly pets, the objects appear dim or the contours fade. 

He’s in a strange new world and even your gently approaching hand might scare him, hence the fearful reaction.

The same goes for the loss of hearing. 

In the good old days, your dog could recognize the footsteps of every member of the family even when he was dozing off in his corner. 

Now that he cannot hear that well anymore, you bet he’s startled when you appear in front of him all of a sudden. 

And he flinches. 

You’d do the same in his place.

The vet might be able to help with the eyesight, but there’s little he can do about the hearing loss. 

If this is the case with your pet, you’ll have to learn to live with it. 

The best thing is to avoid going near the dog when he’s not aware of your presence to avoid scaring the wits out of him.

Sudden flinching caused by a traumatic experience

When your dog starts behaving strangely and there’s no physical problem causing it, you need to start examining what recent event might have caused this strange reaction.

If the dog is always in your care you can safely rule out him being kicked or abused in any way. 

On the other hand, if your dog was recently left at daycare or with a minder you barely know, him being abused is a possibility you need to consider. 

There have been cases of dogs being kicked at the doggy daycare. 

Now, don’t jump to conclusions and start making accusations you cannot prove, but you might want to reconsider your options and make different arrangements for your beloved pet.

At the same time, there are many other situations that might be traumatic to a dog. Have you recently moved house? 

Is someone new living in your house, a baby or a new partner? 

Has someone left?

Moving house is pretty stressful for humans and even more so for a dog who finds himself in an unfamiliar place. 

If this is the case, make sure your pet has his sleeping quarters just as he used to, unpack all his favorite toys and give him time to adapt.

How to deal with a dog flinching all of a sudden

 First of all you need to determine if there’s a physical problem causing this behavior. 

An injury or an infection will probably go away soon enough, or if he’s diagnosed with seizures he will be put on medication to ease the symptoms. 

With physical issues you can expect the dog to stop doing that awful flinching movement once the underlying cause is dealt with.

On the other hand, if it’s entirely in his mind you need to show understanding and help the dog work it out.

  • If it’s about the second fear period, he will outgrow it in due time, don’t worry.
  • Do not force the dog to go near the object or person he seems to be afraid of.
  • Let him be, even if this means cowering in his safe space.
  • Let him get near you or whatever scares him when he feels comfortable.
  • Consider giving your dog more opportunities to socialize.
  • Take him to a doggy park and let him have fun to relieve whatever stress he might be dealing with.
  • If nothing helps, look for a canine behaviorist or a dog trainer and get their advice.

In any case, don’t resent your dog for flinching all of a sudden. It’s got nothing to do with you.

Closing thoughts

There’s always a reason when a dog starts flinching all of a sudden. 

Maybe he’s going through a fear stage, which is quite natural and will go away.

If there’s a physical problem making your dog flinch, like pain or loss of vision, you need to take him to the vet and, in most cases, this behavior will go away once the underlying problem is solved.

If there’s no cause for his behavior or nothing you can think of, just bear with him and wait till it gets sorted out in his head.

James Grayston

My name is James and I love dogs. have owned four Golden Retrievers in the past 15 years. Currently I own two "Goldies"- a five year old and a seven month old. The photo shows me with our youngest when she was about 7 weeks old!