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 think might be poisonous, call 911 or 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 Center 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).
- Coral snake (family Elapidae).
- Gila monster and Mexican beaded lizard.
Maine, Alaska, and Hawaii are the only states that do not have at least one poisonous snake species in the wild.
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. If poison is released in the bite, about 35% of the bites have mild injections of poison (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. And a dead snake, even one with a severed head, can still bite and release venom by reflex action for up to 90 minutes after it dies. Even if you do not develop symptoms within 8 hours, continue to watch for symptoms for 2 weeks or more.
Nonpoisonous snake or lizard bite
Most snakes and lizards in North America are not poisonous. Bites may be frightening, but most do not cause serious health problems. A bite from a small nonpoisonous 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 nonpoisonous snakebites can be treated at home, a bite from a large nonpoisonous 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 may 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 nonpoisonous 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.
Emergencies
Do you have any of the following symptoms that require emergency treatment? Call 911 or other emergency services immediately.
- Bite from a known or suspected poisonous snake or lizard
- Signs of shock:
- Moderate to severe breathing problems:
- Changes in level of consciousness, such as loss of consciousness, confusion, or extreme sleepiness
- Severe immediate pain with rapid swelling at the site of the bite
- Numbness or tingling at or near the bite site or around the mouth, tongue, scalp, or feet
- Drooling, slurred speech, or rapid swelling of the mouth, tongue, or throat
Note: Take the following immediate first aid steps after a suspected poisonous snake or lizard bite:
- Remain calm.
- Do not use any type of tourniquet.
- Do not use any type of extraction device.
- Keep the bitten extremity in a neutral position if possible. You do not need to raise it or lower it below the level of the heart.
Check Your Symptoms
If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.
Review health risks that may increase the seriousness of your symptoms.
| Note: | If you are not sure what type of snake or lizard bit you, call the Poison Control Center immediately to help identify the snake or lizard and determine the next steps to take. Medicine to counteract the effects of the poison (antivenom) can save a limb or your life. |
Have you been bitten by a large nonpoisonous snake, such as a boa constrictor, python, or anaconda?
See significance of a bite from a large nonpoisonous snake if you need information to help you answer the questions below.
Review health risks that may increase the seriousness of your symptoms.
Call your health professional immediately if you answer "Yes" to any of the following questions.
Do you have tingling, burning, numbness, or a "pin-and-needles" feeling (paresthesia) below the bite injury?
Are you unable to move your limb normally (not because of pain) below the bite?
Do you have severe pain below a bite that is not part of the bite?
Did a lot of swelling develop within 30 minutes of the bite?
Do you have nausea or vomiting?
Do you have mild difficulty breathing?
Call your health professional today if you answer "Yes" to the following question.
Were you bitten by a very large snake (such as a boa constrictor, python, or anaconda), and you have no other symptoms?
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
See significance of an infection if you need information to help you answer the questions below.
Review health risks that may increase the seriousness of your symptoms.
Call your health professional immediately if you answer "Yes" to any of the following questions.
Do you have a bite on a leg or foot and peripheral arterial disease?
Do you have a disease or take medicine that causes problems with your immune system?
Do you have red streaks extending from the bite?
Call your health professional today if you answer "Yes" to any of the following questions.
Do you have increased pain, swelling, redness, or warmth around the bite?
Is the area around the bite becoming more tender to the touch?
Do you have pus in, around, or draining from the bite?
Do you know or think you have a fever?
You may wait to see if the symptoms improve over the next 24 hours (or specified time period) if you answer "Yes" to any of the following questions.
Have you had mild pain and swelling with redness less than 1 in. (2.5 cm) around the bite for 24 hours or longer?
Have you had swollen glands (lymph nodes) in your neck, armpit, or groin for 1 week or longer?
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
Do you think a snake's or lizard's tooth is still in the wound?
See significance of a tooth still in the wound if you need information to help you answer the questions below.
Review health risks that may increase the seriousness of your symptoms.
Call your health professional today if you answer "Yes" to any of the following questions.
Do you think a tooth is still in the wound, and you are unable to remove it?
Are you unable to remove a tooth from the wound?
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
Do you know or think you need a tetanus shot?
See significance of getting a tetanus shot if you need information to help you answer the question below.
Review health risks that may increase the seriousness of your symptoms.
| Note: |
If you need a tetanus shot, call your doctor to arrange for a shot.
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Call your health professional today if you answer "Yes" to any of the following questions.
Are you worried that the bite area has gotten dirty or has germs on it and your last tetanus shot was longer than 5 years ago?
| Note: | Something is dirty if it has dirt, soil, spit, or feces on it. |
Are you not sure when you had your last tetanus shot?
Did you not get the first series of tetanus shots?
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
Have your symptoms continued after home treatment or medical treatment?
See significance of home or medical treatment not relieving symptoms if you need information to help you answer the questions below.
Review health risks that may increase the seriousness of your symptoms.
Call your health professional today if you answer "Yes" to any of the following questions.
Have your symptoms gotten worse since seeing your doctor?
Have you seen your doctor, but the prescribed medical treatment has not helped your symptoms in 2 days or in the time frame given by your doctor?
You may wait to see if the symptoms improve over the next 24 hours (or specified time period) if you answer "Yes" to the following question.
Have your symptoms continued after 3 to 4 days of home treatment? Symptoms may include:
- The bite area does not seem to be healing as you expected.
- General feeling of illness.
If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.
Other Symptoms to Watch For
Do you have the following symptom?
- Bleeding from a snake or lizard bite: Go to one of the following topics:
If a visit to a health professional is not needed immediately, see the Home Treatment section for self-care information.
Home Treatment
Poisonous snake or lizard bite
If you were bitten by a snake or lizard that you know or think is poisonous, call 911 or other emergency services immediately. Do not wait for symptoms to develop. Symptoms may progress from mild to severe rapidly.
If you are not sure what type of snake or lizard bit you, take a picture of it. But do not do this if it will delay treatment or put someone at risk for additional bites. Do not waste time or take any risks trying to kill or bring in the snake. Only trap a poisonous snake if the chances are good that it will bite more people if you let it go. It is important to remember that a snake only injects part of its venom with each bite, so it can still hurt you after the first strike. And a dead snake, even one with a severed head, can still bite and release venom by reflex action for up to 90 minutes after it dies.
Medicine (antivenom) to counteract the effects of the poison can save a limb or your life. Antivenom is given as soon as a doctor determines it is needed, usually within the first 4 hours after the snakebite. Antivenom may be effective up to 2 weeks or more after a snakebite.
Immediate home treatment
Immediate home treatment should not delay transport for emergency evaluation.
- Remain calm and try to rest quietly.
- If you are not sure what type of snake or lizard bit you, call a Poison Control Center immediately to help identify the snake or lizard and find out what to do next.
- If signs of shock are present or the bitten person is not breathing, see the topic Dealing With Emergencies.
- Remove any jewelry. The limbs might swell, making it more difficult to remove the jewelry after swelling begins.
- Use a pen to mark the edge of the swelling around the bite every 15 minutes. This will help your doctor estimate how the venom is moving in your body.
Avoid these treatment measures
Avoid doing anything that might cause more problems with the snake or lizard bite.
- Do not cut the bite open.
- Do not suck on the bite wound or use any kind of extraction device.
- Do not use a constriction band, such as a tourniquet or bandage, on a bite.
- Do not soak your hand or foot in ice water or pack your arm or leg in ice. This can increase damage to the skin and cause a cold-induced injury, such as frostbite.
- Do not raise the bitten arm or leg above your head. This may increase the flow of venom into the bloodstream.
- Do not drink alcohol.
- Do not give any prescription or nonprescription medicines after a poisonous snake or lizard bite unless your doctor tells you to. Some medicines, such as aspirin, ibuprofen, or naproxen, may cause increased bleeding.
Nonpoisonous snake or lizard bite
If you are certain the snake or lizard was not poisonous, use home treatment measures to reduce symptoms and prevent infection.
- Use direct pressure to stop any bleeding. See how to stop bleeding.
- Look at the wound to make sure a snake or lizard tooth is not in the wound. If you can see a tooth, remove it with tweezers, taking care to not push it farther into the wound.
- Clean the bite as soon as possible to reduce the chance of infection, scarring, and tattooing of the skin from dirt left in the wound. Wash the wound for 5 minutes with large amounts of warm water and soap (mild dishwashing soap, such as Ivory, works well). See how to clean a wound.
- Do not use rubbing alcohol, hydrogen peroxide, iodine, or mercurochrome, which can harm the tissue and slow wound healing.
- Soak the wound in warm water for 20 minutes, 2 to 4 times a day, for the next 4 to 5 days. The warmth from the water will increase the blood flow to the area, which helps reduce the chance of infection.
- Puncture wounds usually heal well and may not need a bandage. You may want to use a bandage if you think the bite will get dirty or irritated.
- Clean the wound thoroughly before putting the bandage on it.
- Apply a clean bandage when it gets wet or soiled. If a bandage is stuck to a scab, soak it in warm water to soften the scab and make the bandage easier to remove.
- If available, use a nonstick dressing. There are many bandage products available.
- Be sure to read the product label for correct use.
- Use of an antibiotic ointment has not been shown to affect healing. If you choose to use an antibiotic ointment, such as polymyxin B sulfate (for example, Polysporin) or bacitracin, apply the ointment lightly to the wound. The ointment will keep the bandage from sticking to the wound. If a skin rash or itching under the bandage develops, stop using the ointment. The rash may be caused by an allergic reaction to the ointment.
- Determine whether you need a tetanus shot.
- An ice or cold pack may help reduce swelling and bruising. Never apply ice directly to a wound or the skin. This could cause tissue damage.
| Try a nonprescription medicine to help treat your fever or pain: |
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| Be sure to follow these safety tips when you use a nonprescription medicine: |
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For more information on cuts, scrapes, or puncture wounds, see the topics Cuts, Scrapes, or Puncture Wounds in the Related Information section of this topic.
Symptoms to Watch For During Home Treatment
Use the Check Your Symptoms section to evaluate your symptoms if any of the following occur during home treatment:
- Symptoms of a pit viper snakebite develop.
- Symptoms of a coral snake bite develop.
- Symptoms of a skin infection develop.
- A wound does not heal.
- Symptoms become more severe or more frequent.
Prevention
Snakebites are more likely to occur in warm-weather months when both snakes and people are more active outdoors. Most snakebites occur on the fingers, hands, and arms when someone is working with or trying to catch a snake. The legs and feet are also common bite sites; these bites usually occur when a person (especially a child or a hiker) accidentally disturbs a snake.
Snakes and lizards are popular exotic pets, so the risk for being bitten has increased.
Many snake and lizard bites can be prevented.
- Find out what local snakes and lizards are found in your area. Learn what they look like, whether they are poisonous, and where you are most likely to see them.
- If you see a snake or lizard, do not bother it. Keep in mind that the striking range of a snake is about two-thirds of its length.
- Do not pick up or handle snakes. Even a dead snake can bite and release venom through reflexes for 90 minutes or more after it dies.
- Watch for snakes around wood or rock piles or caves. Wear protective shoes, boots, and clothing when you are hiking, camping, fishing, and hunting.
- Do not drink alcohol or use illegal drugs while doing outdoor activities where you might encounter a snake. The effects of the alcohol and drugs may slow your judgment and reflexes.
- If you have a pet snake or lizard or are thinking about getting one, learn how to handle it safely to avoid being bitten. Find out what first aid supplies you will need if you are bitten, and have them handy.
If you are often in an area where there are poisonous snakes, consider carrying a first aid kit. Carry a cellular phone, if you have one, to call for help if you are bitten.
Preparing For Your Appointment
To prepare for your appointment, see the topic Making the Most of Your Appointment.
You can help your doctor diagnose and treat your condition by being prepared to answer the following questions:
- Do you know what type of snake or lizard bit you? What did the snake or lizard look like? How big was the snake or lizard? Did it rattle?
- When did the bite occur?
- Where were you bitten?
- How many times were you bitten?
- What are your main symptoms? How long have you had your symptoms?
- What home treatment measures have you tried? Did they help?
- What nonprescription medicines have you tried? Did they help?
- Have you been treated for a snakebite in the past? If yes, what type of treatment did you receive?
- What prescription and nonprescription medicine do you take?
- How long ago was your last tetanus shot?
- Do you have any health risks?
Credits
| Author | Jan Nissl, RN, BS |
| Editor | Susan Van Houten, RN, BSN, MBA |
| Associate Editor | Tracy Landauer |
| Primary Medical Reviewer | William M. Green, MD - Emergency Medicine |
| Specialist Medical Reviewer | Sean P. Bush, MD, FACEP - Emergency Medicine and Envenomation Specialist |
| Last Updated | June 19, 2008 |
