Adder Bite Dog Symptoms: How to Know Your Dog Was Bitten

adder bite dog symptoms

We live near the New Forest down on the south coast of England and frequently take our dog Claude for walks in the national park. It’s great exercise for all of us, but this summer there has been an increase in adder sightings which has made us extra cautious.

In fact, there was one day only last week where we thought for a moment that Claude had been bitten by a snake. He was showing what we thought were signs of an adder bite in a dog with swelling and limping, and had some clear discomfort walking.

However, after a quick vet examination it turned out he had actually been stung by an insect. It was a huge relief for us, and he was back to his normal self soon after.

Whilst at the vets, we were given a fact sheet which explained how to know if your dog has been bitten by an adder. It listed the key symptoms of an adder bite in a dog, and what you need to do if your suspect your dog has been bitten by this snake.

To help out other people online, I decided to replicate those signs and symptoms here which you can refer to in case the same thing happens to you. It also includes a photo lower down of what an adder bite looks like on a dog.

Symptoms of adder bite in dogs

Adders are very shy creatures and will usual slink off into the grass or bush as soon as they hear any noise of activity near them. However, due to the speed of dogs and their in-built prey drive, it’s not uncommon for them to corner an adder. The snake will then feel threatened and bite the dog.

symptoms of adder bite in dogs
We saw this adder in the New Forest when walking our dog this summer.

Due to the mix of chemical compounds in their venom, the symptoms of adder bites in dogs can be very varied. Here are the signs to look for.

1. Two puncture wounds from the fangs

Immediately after an adder bite, there will be two small red dots on the skin about a centimetre apart. However, depending on where the bite was, and the hair of your dog, it might not be possible to see this particular adder bite symptom.

You might also see fluid or blood seeping from the bite marks.

2. Rapid swelling around the bite location

Very quickly after the bite, the wound will start to swell up, and will be a dark red colour compared to your dog’s skin in the minutes following the attack. After 2 hours it will be a noticeable bump on your dog’s skin.

This skin inflammation and bruising occurs as the venom starts to spread through the blood.

3. Change in your dog’s behaviour

After an adder bite, your dog will be confused and nervous. People I know whose dogs have been bitten have immediately been alerted to the fact by their dog acting all skittish and weird.

If it was a bite to the leg, look out for them picking the leg up and hobbling or walking in a strange manner. If it’s a bite to the face, they might start pawing at it.

signs of adder bite in dogs
Adders are common in the New Forest, and you should know if your dog has been bitten by one due to a sudden change in behaviour.

Please note: the following symptoms are very rare

In very rare cases, there can be complications, including the following symptoms. This is unusual though in dog adder bites, as most dogs will recover very quickly with little medical attention.

4. Very rare: Signs such as drooling, lethargy, and vomiting

Once the adder venom gets into your dog’s system you can start to see more obvious symptoms of an adder bite. In dogs, as well as the obvious signs of pain, some of these symptoms could also be related to other conditions.

The only way you will know will be to seek the professional advice of your vet, so if you suspect an adder bite, get to professional help immediately.

5. Very rare: Breathing difficulties

Panting is one of the more serious adder bite in dog symptoms. But is almost unheard of apart from in exceptional cases. Heavy breathing will be seen due to your dog having an allergic reaction to the adder venom, typically when bites occur on the head and neck.

Your dog’s heart rate could increase, and some will also show pale gums when breathing.

6. Very rare: Lameness and collapse

In the most serious of cases, and in the rare fatalities recorded, the adder venom absorbs into your dog’s body. It can lead to an inflammatory reaction which results in blood clots, fever, tremors, and an eventual collapse.

How do I know if my dog has been bitten by an adder?

Aside from the symptoms of adder bites listed above, your dog’s behaviour will also be a key indicator to whether they have been bitten.

In many cases you won’t even see the adder that bit your dog. The first sign your dog has been bitten by an adder will be a loud yelp and sudden movement from your four-legged friend, followed by limping.

Most adder bites in dogs are on the face or legs, so check those first if you believe your dog might have been bitten. You should look for two red dots, followed by swelling as described in the dog adder bite symptoms already mentioned.

What to do when your dog gets bitten

  • Get away from the adder: Do not scare aware the snake, instead just get you and your dog away from it as soon as possible as it might strike again.
  • Call the vets: As soon as your dog is bitten by an adder, call your vet to discuss the options. Very few vets carry adder antivenin, so they may just recommend and antihistamine.
  • Do not use a tourniquet: Cutting off your dog’s blood supply to the bite will restrict blood flow. This can result in necrosis (see definition) which is where body tissue and cells die.
  • Do not suck the venom out: Despite this often being seen in films, it’s actually ineffective as the adder’s venom is already in your dog’s bloodstream. You will not be able to suck it back out, no matter how hard you try.
  • Don’t let your dog walk or run: The more your dog is active, the quicker his blood will pump around his body. As the blood pumps faster, it will spread the venomous toxins quicker and has been a contributory factor in the rare deaths.
  • Keep calm at all times: Instead try and carry your dog to the car instead, whispering and petting him to keep him calm. If you remain calm, your dog’s heart rate will not speed up as much, therefore won’t pump blood as quickly.

Handy Hint: Some owners and vets will use Piriton antihistamine on dogs who have been bitten by adders. You can read more about what the experts say on this in my research into whether it’s safe.

What does an adder bite look like on a dog?

Aside from the two red dots, once the venom starts to spread, you will see visible swelling.

Can a dog survive an adder bite?

In the majority of cases, most dogs will survive adder bites. For example, in 2015 the Veterinary Poisons Information Service reported 101 adder bites to dogs in the UK. Of those 101 cases, 5 of the dogs died, giving a 4.9% fatality rate.

The remaining 95.1% of dogs will make a full recovery from an adder bite within 5 days or less, providing they have had immediate veterinary attention. Pain relief is the usual treatment given.

Handy Hint: I’ve compiled statistics on snake bites which show how likely it is that a dog would die from an adder bite.

Whether the dog survives the adder bite will depend on a range of factors including:

  • The age and size of the dog: Smaller and older dogs are more at risk and have lower survival rates. Smaller dog breeds have a higher body size to venom ratio so cannot absorb as much of the adder bite venom as larger breeds could.
  • The location of the bite: Dogs are more likely to survive adder bites when they are bitten on the leg or face. Blood supply to these areas will be slower, whereas a bite to the dog’s tongue has a higher rate of fatality.
  • The strength and volume of venom: Whether a dog lives from an adder bite will also depend on how much venom was injected. If the adder hasn’t bitten something in a while, the venom will be stronger and administered in more volume if it’s been saved up for a period of time.
  • How long it takes to get treatment: The sooner you get medical help the better your dog’s change of survival will be. Ideally you need to get the dog to a vet inside of 30 minutes for the best prognosis.
  • How active your dog has been since the bite: Your dog has a better chance of surviving an adder bite if he’s kept still and calm after the strike. This will slow down his blood flow around the body, meaning the toxins won’t reach the essential organs as quickly.

Treatment for adder bites in dogs

Not all dogs will be given antivenoms after an adder bite. It’s only used in the most serious of cases. The Veterinary Record website published the following statistics for treatment in 2011:

“The Veterinary Poisons Information Service reviewed 422 telephone inquiries concerning dogs with adder bites received between 1985 and 2010. European adder antivenom was used in 56% of cases, steroids in 51%, antibiotics in 56% and antihistamines in 20%. Among dogs treated with antivenom, case fatality was slightly lower than in the rest (0.3% versus 0.5%, though not statistically significant) and swelling resolved more rapidly (47 hours on average versus 94 hours). Although antivenom is not required for the management of every case of adder bite, it is usually recommended for potentially serious cases.”

Depending on the symptoms and how serious it is, many will be given antihistamines, pain relief, and possibly a drip to maintain their blood pressure.


Whilst the signs of adder bites in dogs listed in this guide along with the symptoms do make for sobering and scary reading, bites are actually quite rare.

Most snakes will only ever bite when they feel cornered and in self-defence, so it’s up to us as owners to prevent this happening in the first place.

You might also like…

I regularly write about dogs and snakes, so you might find the following articles of interest:

Marc Aaron

I write about the things we've learned about owning dogs, the adventures we have, and any advice and tips we've picked up along the way.

Recent Posts