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Venomous Snakebites

What are venomous snakebites?

A venomous snakebite is a bite from a venomous snake where venom, a poison (toxin) is injected into the victim’s body. The bite can cause injury. In rare cases, it can be fatal.

According to the CDC, about 8,000 snakebites happen in the U.S. each year. Even a bite from a harmless snake can cause infection or allergic reaction in some people. For your safety, treat all snakebites as if they were venomous. Get to a hospital emergency room as quickly as possible.

Sometimes a venomous snake can bite you without actually injecting venom into you. This is called a dry bite. This can occur in 20 or 25 out of 100 pit viper snakebites. And it can happen in half of all coral snakebites.

Which snakes cause venomous bites?

The most common venomous snakebites are caused by these snakes in the U.S.:

  • Pit vipers. These include rattlesnakes, copperheads, and cottonmouth (water moccasin) snakes. These snakes have a venom that destroys skin and muscle. It also causes problems with your blood.

  • Coral snakes. These snakes have a venom that affects your nerves and can cause paralysis.

Rattlesnake bites cause most of the venomous bites in the U.S. Coral snakes and imported exotic snakes cause a much smaller number of snakebites.

Other native snakes in the U.S. don’t have venom.

What are the symptoms of venomous snakebites?

Different snakes have different types of venom. The symptoms may differ. In general, pit vipers have a venom that destroys skin and muscle. Coral snakes have a neurotoxic venom that attacks the nerves. These are the most common symptoms of venomous snakebites:

  • Bloody wound discharge

  • Excessive bleeding and trouble with blood clotting

  • Fang marks in the skin and swelling at the bite site

  • Severe pain at the bite site

  • Discoloration, such as redness and bruising or blood blisters

  • Enlarged lymph nodes in the affected area

  • Diarrhea

  • Burning

  • Convulsions

  • Fainting

  • Dizziness

  • Weakness

  • Blurred vision

  • Excessive sweating

  • Fever

  • Increased thirst

  • Loss of muscle coordination

  • Nausea and vomiting

  • Numbness and tingling, especially in the mouth

  • Fast pulse

  • Trouble breathing

  • Change in mental state

  • Paralysis

  • Shock

The symptoms of a venomous snakebite may look like other health conditions or problems. Always see your healthcare provider for a diagnosis.

How are venomous snakebites diagnosed?

Diagnosis is made by making a clear identification of the snake. The severity of the venom injection into the person’s body is also graded. Venomous snakebites can cause 2 types of poisoning:

  • Localized poisoning. This affects only the area where the bite occurred.

  • Systemic poisoning. This affects the entire body.

All snakebites should be considered venomous until proved otherwise. This is done by a clear identification of the snake or by a period of clinical observation.

The healthcare provider will take a full history. This includes:

  • Time of the bite

  • Description of the snake

  • Type of first aid given

  • Underlying health conditions

  • Allergy to horse or sheep products

  • History of past venomous snakebites and therapy

A complete physical exam will also be done. A mark will be made on the first part of the swelling on the affected limb or area. The time the mark was made will be recorded.

Sometimes the person can’t recall details about the snake. Then a consultation with a zoo, aquarium, or poison control center (800-222-1222) may be used to help identify the type of snake.

How are venomous snakebites treated?

Call for emergency help right away if you have been bitten by a snake. Responding quickly in this type of emergency is vital. While waiting for emergency help:

  • Wash the bite with soap and water.

  • Keep the bitten area still and lower than the heart.

  • Cover the area with a clean, cool compress or a moist dressing to ease swelling and discomfort. If the bite is from a coral snake, consider applying some firm pressure directly over the wound with a clean cloth and your hand.

  • Watch breathing and heart rate.

  • Remove all rings, watches, and constrictive clothing, in case of swelling.

  • Note the time of the bite so that it can be reported to an emergency room healthcare provider if needed.

  • If possible, try to remember to draw a circle around the affected area. Mark the time of the bite and the first reaction. If you are able, redraw the circle around the site of injury, marking the progression of time.

  • It’s helpful to remember what the snake looks like, its size, and the type of snake if you know it. Tell this to the emergency room staff.

  • Don't apply a tourniquet. This will cause more damage. It actually worsens your outcome and makes it more likely that you could lose your arm and or leg. That is because it keeps all of the toxin in one place and gives it more time to cause damage. It also cuts off blood supply to any healthy tissue, causing more damage.

  • Don't try to suck the venom out. Doing this will only introduce infection and cause more damage.

  • Don’t apply ice.

At the emergency department you may be given:

  • Antibiotics to prevent or treat developing infections

  • Medicine to treat your pain

  • A special type of medicine (antivenin), depending on the type of snake that bit you and the severity of your symptoms

Can venomous snakebites be prevented?

Some bites are nearly impossible to prevent. These include a snake that bites you when you accidentally step on it in the woods. But you can take steps to reduce your chances of being bitten by a snake. These include:

  • Leaving snakes alone. Many people are bitten because they try to tease, kill, or get too close to the snake.

  • Staying out of tall grass unless you wear thick leather boots and long pants. Stay on hiking paths as much as possible.

  • Keeping hands and feet out of areas you can't see. Don't pick up rocks or firewood unless you are out of a snake's striking distance.

  • Being careful and alert when climbing rocks. Don't stick your hands into rock crevices.

If you often spend time in wilderness areas, camp, hike, picnic, or live in snake-inhabited areas, learn the possible dangers posed by venomous snakes. You should:

  • Know how to identify venomous snakes

  • Be able to get to medical help in case of emergency

  • Be aware that snakes are more active during warmer months

Key points about venomous snakebites

  • A venomous snakebite is a bite from a venomous snake where venom, a poison (toxin) is injected into the victim’s body

  • This type of bite can cause injury. In rare cases, it can be fatal.

  • Rattlesnake bites cause most of the venomous bites in the U.S. Coral snakes and imported exotic snakes cause a much smaller number of snakebites.

  • For your safety, treat all snakebites as if they were venomous. Get to a hospital emergency room as quickly as possible.

  • Treatment may include antibiotics and medicine to treat pain. Antivenin may be given, depending on the type of snake and the symptoms.

  • If you spend time in wilderness areas, know how to identify venomous snakes, how to care for snake bites, and how to get emergency medical help.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

Online Medical Reviewer: Eric Perez MD
Online Medical Reviewer: Marianne Fraser MSN RN
Online Medical Reviewer: Maryann Foley RN BSN
Date Last Reviewed: 4/1/2021
© 2000-2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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