Snake and Lizard Bites
Topic Overview
Poisonous snake or lizard bite
A bite from a poisonous (venomous) snake or lizard requires emergency care. If you have been bitten by a snake or lizard that you know or suspect might be poisonous, call911or other emergency services immediately. Do not wait for symptoms to develop.
If you are not sure what type of snake or lizard bit you, call the poison control centre immediately to help identify the snake or lizard and find out what to do next. Medicine to counteract the effects of the poison (antivenom) can save a limb or your life.
It is important to stay calm.
Poisonous snakes or lizards found in North America include:
- Pit vipers (family Viperidae), such as the rattlesnake, copperhead, and water moccasin (also called cottonmouth). Rattlesnakes are the only pit vipers found in the wild in Canada.
- Coral snake (family Elapidae). Coral snakes are not found in the wild in Canada.
- Gila monster and Mexican beaded lizard. Gila monsters and Mexican beaded lizards are not found in the wild in Canada.
Poisonous snakebite
Symptoms of a pit viper snakebite often appear from minutes to hours after a bite. Severe burning pain at the site usually begins within minutes, and then swelling starts spreading out from the bite.
Factors that affect the severity of a poisonous snake or lizard bite include the:
- Type and size of the snake or lizard.
- Amount of venom injected (if any).
- Potency of the venom injected.
- Location and depth of the bite.
- Number of bites and where they occurred on the body.
- Age, size, and health of the person who was bitten.
If you do not develop symptoms within 8 to 12 hours, it is possible that no venom was injected; this is called a dry bite. At least 25%, perhaps up to 50%, of bites are dry. When poison is injected, about 35% of bites are mild envenomations, 25% are moderate, and 10% to 15% are severe.
It is important to remember that a snake only injects part of its venom with each bite, so it is still dangerous after the first strike. A bite from a young snake can be serious. A dead snake can have a bite reflex after death, so it must be considered dangerous as well. Even if you do not develop symptoms within 8 hours, continue to watch for symptoms for 2 weeks or more.
Non-poisonous snake or lizard bite
Most snakes and lizards in North America are non-poisonous. Bites may be frightening, but most do not cause serious health problems. A bite from a small non-poisonous snake might leave teeth marks, a minor scrape, or a puncture wound without other symptoms. Home treatment often relieves symptoms and helps prevent infection.
Although most non-poisonous snakebites can be treated at home, a bite from a large non-poisonous snake (such as a boa constrictor, python, or anaconda) can be more serious. In North America, these snakes are often found in zoos, but they are also be kept as exotic pets. The force of the bite can injure the skin, muscles, joints, or bones. Other problems can occur with a non-poisonous snake or lizard bite even if the reptile is small. A snake or lizard's tooth may break off in a wound or a skin infection may develop at the site of the bite.
Review the Emergencies and Check Your Symptoms sections to determine if and when you need to see a doctor.
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| Author: | Susan Van Houten, RN, BSN, MBA | Last Updated: August 31, 2006 |
| Medical Review: | William M. Green, MD - Emergency Medicine Adam Husney, MD - Family Medicine Tom Bailey, MD - Family Medicine Sean P. Bush, MD, FACEP - Emergency Medicine and Envenomation Specialist | |
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| Topic Contents | |
 | Topic Overview |
| Emergencies | |
| Check Your Symptoms | |
| Home Treatment | |
| Prevention | |
| Preparing For Your Appointment | |
| Related Information | |
| Credits | |