Snakebite

Are all snakebites dangerous?

Some snakes are poisonous and some are not. Even poisonous snakes may not always release venom when they bite. Other snakes may release too small an amount to pose a hazard. However, a bite from a poisonous snake must always be treated as a medical emergency. If you have been bitten by a snake and you do not know if the snake is poisonous, treat the bite as a poisonous snakebite. In the US, most poisonous bites are by pit vipers, including rattlesnakes, copperheads, and water moccasins (also called cottonmouths). Coral snakes are a less common type of poisonous snake found in the US.

A bite from a nonpoisonous snake can cause an infection or allergic reaction in some people. You should get medical care as soon as possible for any snakebite.

What are the signs and symptoms of a snakebite?

The signs and symptoms can vary, depending on if and how much venom got into your body, your size and health, the location and depth of the bite, and how soon you get effective treatment.

The signs of any snakebite may include:

at least one puncture wound from the fangs
bleeding
swelling.

When a poisonous snake releases venom into the bite (envenomation), other symptoms may be:

a burning feeling that may turn into overwhelming pain
tingling of the lips and tongue
discoloring of the skin, including blackness if the skin tissue is dying
very severe muscle cramps
blurred vision
dizziness
excessive sweating
fainting
loss of muscle coordination
weakness
rapid pulse
nausea and vomiting.

The symptoms caused by venom may not appear until hours after a bite even though the poison might be quite deadly. For this reason, it is always important to get immediate medical attention for any bite that may be poisonous.

What is the first aid for poisonous snakebites?

All snakebites should be treated as poisonous unless you are sure that the snake was nonpoisonous.

If the snake is poisonous or you are not sure if it is poisonous, immediately follow these first aid steps:

Move the person to safety.
Keep the person calm and quiet. Keep them from moving too much.
Remove any jewelry or tight-fitting clothing that is below the bite.
Make sure the bitten area is kept still, for example, by using a splint. Keep it lower than the heart.
Get medical help right away.

If it will be longer than 30 minutes before medical help is available:

Wash the bite with soap and water.
Apply a light restricting band (not a tourniquet) 2 to 4 inches above the bite to help slow the movement of venom. The band should be loose enough that a finger can slip under it and a pulse can be felt below the band. You might use an elastic bandage or torn clothing for the band.

The purpose of first aid is to protect the person who has been bitten from further harm and to limit the spread of snake venom. There are several things you should NOT do for snakebites:

Do not apply a tourniquet. It will cut off circulation and may lead to a loss of the arm or leg.
Do not cut the bite. This may cause more injury.
Do not try to use a suction device or your mouth to draw venom out of the wound.
Do not use ice or any other type of cooling on the bite. This can cause further injury.
Do not use electric shock. It does not neutralize venom and may make the situation worse.
Do not waste any time trying to kill or catch the snake.

What is the first aid for nonpoisonous snakebites?

To apply first aid for nonpoisonous snakebites:

Wash the bite with soap and water.
Put a simple bandage or gauze dressing on the wound, if needed.
Make sure your tetanus shots are up-to-date. If it has been 5 or more years since your last tetanus shot, get a shot as soon as possible, preferably the same day as the bite.
Get medical care for nonpoisonous snakebites if:
- The bite wound is bleeding and does not stop bleeding.
- Over the next few days you develop signs of infection: redness around the bite or red streaking from the bite toward the body, fever, or increasing pain at the site of the bite.

What is the medical treatment for poisonous snakebites?

If you have been bitten by a poisonous snake and venom was released into the bite, medical treatment may include giving a medicine called antivenin or antivenom. It is given as a shot or intravenously (IV). The antivenin neutralizes any snake venom that is in the body. It is best to receive this medicine within 4 to 6 hours of a bite, but it may be given as long as 24 hours after a bite.

Antivenin is made from a sheep or horse's blood serum after the animal has been infected with snake venom. Some people are very allergic to medicines, especially those made from horse serum. For this reason, you may be tested for an allergy to the antivenin before it is given to you. However, in some cases it will be given without the testing, in order to get it working as fast as possible.

Anyone who has been bitten by a snake will be watched very closely for reactions to the bite or antivenin. This will determine the course of treatment.

You may also get a tetanus shot to prevent tetanus in case any dirt and bacteria entered the skin with the bite.

How long will the effects of venom last?

If venom has entered your body, antivenin can effectively reverse the effects of venom and save your life. But there is no guarantee that antivenin can reverse damage already done, such as the death of some of your tissue. In some cases skin grafts or other treatment may be needed. This is why it is important to get medical treatment as soon as possible after a snakebite.

Snakebites can cause bleeding problems. Contact your health care provider right away if you experience bruising, nosebleeds, excessive bleeding of your gums after brushing your teeth, blood in your bowel movement, or heavy menstrual bleeding.

How can I prevent snakebites?

If possible, avoid areas with snakes.

Before you visit, hike, or camp in a new area, do the following:

Learn about the snakes that may live in the area.
Learn the proper first aid for a snakebite.
Know where the closest medical facility is in case of an emergency.

Take precautions when you visit snake regions:

Wear long pants and boots.
Stay on hiking paths
Be cautious and alert when you climb rocks.
Do not pick up firewood or rocks unless you are sure that you are out of a snake's striking distance. (A snake can strike half its length.)
Take a mobile phone with you.
Leave snakes alone. Do not try to kill a snake or get a closer look. Stay at least 6 feet away from any snakes you encounter.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File SFY4936F.HTM Release 9.0/2006