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Rattlesnake bites: symptoms, treatment, what to do (and not do)

Updated: May 13

Rattlesnake bite dog

How rattlesnake venom affects pets

A snake’s venom contains at least 10 types of enzymes to break down tissue. Additionally, there are many other non-enzymes present in the venom, called killing fractions, which are 50 times more toxic than the “crude” venom. When the snake venom destroys the body tissues, it is possible for up to a third of a dog’s body fluid to be lost into the tissue spaces within several hours, which can result in life-threatening drops in blood pressure and your dog ending up in shock.

Symptoms of a rattlesnake bite

Snake bites on dogs are not always easy to diagnose, especially if you didn’t see the bite happen or if your dog has a heavy fur coat that may hide puncture wounds. The first thing you might notice is marked swelling, due to the tissue destruction and body fluid “leaking” into the damaged area. Additional clinical signs may develop either immediately or several hours after the snake bite. Bruising and skin discoloration often occurs within hours of the snake bite because the venom causes the blood to not clot. There’s usually intense and immediate pain at the site of the bite, which helps differentiate snake bites from other causes of swelling, such as bee or spider bites, and swelling generally progresses for up to 36 hours. If your pup’s been bitten, they might also collapse, vomit, have muscle tremors, go into shock, or have shallow breathing.

Here is a summary of signs that may indicate a rattlesnake has bitten your dog:

  • Swelling around the area of the bite

  • Bruising and skin discoloration

  • Sudden Collapse

  • Muscle tremors

  • Shallow breathing

  • Lethargy and weakness (ataxia)

  • Bleeding

  • Diarrhea and/or vomiting

  • Dilated pupils

First steps to take if a rattlesnake bites your pet

Seek veterinary attention as soon as possible! Keep your pet calm and immobile, and carry them if necessary. If you can do it safely, take these extra measures prior to transporting to your vet:

  • If the swelling is not in the face, muzzle your dog to avoid being bitten; snake bites are very painful and your dog may unintentionally snap at you. However, if the swelling is in the face, avoid touching this area all together.

  • Immobilize the part of your dog that the snake bit; try to keep the area at or below heart level.

TIP: Learn ahead of time where your closest vet or ER is that carries anti-venom in stock and keep that info handy. If your pet gets bitten by a rattlesnake, you'll already know where to go for treatment, saving precious time.

What NOT to do

  • Don't attempt to treat rattlensnake bites at home

  • Don’t attempt to “make an X” and cut open the area around the bite; you will only cause a wound.

  • Don’t bother to use a Snake Bite Kit or Extractor Pump — they’ll actually do more harm to your dog.

  • Don’t put ice on the snake-bite area. Applying ice constricts the blood vessels locally and actually concentrates the venom, causing severe muscle damage.

  • Don’t rub any substances into the snake bite. At this point, the venom has entered the bloodstream, and any substance applied topically is ineffectual.

  • Don’t apply a tourniquet; you will only succeed in causing further tissue damage and possibly create a need for limb amputation.

  • Don’t allow your pet to move about freely.

  • Don’t attempt to capture the snake for later identification.

Treatment of rattlesnake bites

Because the onset of clinical signs can be delayed for several hours, dogs that have been bitten by a snake should be hospitalized for at least 12 hours and ideally 24. Although most dogs generally need to be supported and monitored for up to a week, the vast majority of dogs — 95% — do survive snake bites with early and proper treatment, so, get your dog to the veterinarian right away.

Antivenom is the only proven treatment against pit viper envenomation, and the earlier it is administered, the more effective. The biggest downside to antivenom is cost; it can range anywhere from $450 to $700 per vial. Usually, a single vial will control the envenomation but several vials may be necessary, especially in small dogs or cats.  Many animals may do “fine” without it, but it does decrease the severity of clinical signs, as well as speed overall recovery with reduced complications.

Blood work is also recommended to monitor your pet’s platelet count as well as clotting times of the blood. IV fluid support, intensive pain management, antibiotics and wound monitoring are required for best outcomes. Blood and plasma transfusions are sometimes needed in severe envenomation.

While there is a “rattlesnake vaccine” available, there have been no controlled studies for its effectiveness. The purported benefit of the vaccine is that it may create protective antibodies to neutralize some of the injected venom, and in turn may lessen the severity of the clinical signs, however, there is just a likely chance that this will increase the potential for anaphylaxis. One of the biggest myths is that if your dog has had the vaccine, they don’t need to be treated if they are bitten; get your pup to the vet ASAP regardless of their vaccine status.

Will my pet survive a rattlesnake bite?

Several factors influence the severity of snake bites. The most important factors are the volume of venom injected and the toxicity of the venom itself. Other factors include:

  • The amount of regenerated venom since the snake's last bite. If the snake hasn’t bitten in a while, when they finally do, they produce more venom and it’s more concentrated.

  • Aggressiveness of the snake. The more threatened they feel, the more concentrated the venom.

  • Motivation of the snake. Offensive strikes are more severe.

  • The size of the pet being bitten. Smaller dogs and cats are more severely affected than larger dogs due to their small body size to venom ratio. Plus, smaller dogs have less body to “absorb” the venom.

  • The size of the bite and location of the bite. The “best” place to be bitten is in the legs or face, as the regional swelling and changes in the local blood supply can actually slow the uptake of the venom; envenomation to the body is more concerning as the broader area allows for the venom to be absorbed more rapidly. Bites to the tongue are the worst and result in rapid and devastating clinical signs.

  • Time. The time elapsed from bite until seeking medical treatment has a significant impact on damage that may occur.

  • A pet’s activity level. The amount of physical activity since the time of the bite.

Read our blog for tips on how to help prevent rattlesnake bites in the first place.

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