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
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
It is important to stay calm.
Poisonous snakes or lizards found in North America include:
Maine, Alaska, and Hawaii are the only states that don't
have at least one poisonous snake species in the wild.
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.
Things that affect the
severity of a poisonous snake or lizard bite include the:
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%, and 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.
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
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
found in the Florida Everglades and 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
Check your symptoms to decide if and when
you should see a doctor.
You have answered all the questions. Based on your answers, you may be
able to take care of this problem at home.
Based on your answers, you need
or other emergency services now.
Based on your answers, you may need care soon. The
problem probably will not get better without medical care.
Based on your answers, you may need care right away. The problem is likely to get worse without medical care.
You may need a tetanus shot depending
on how dirty the wound is and how long it has been since your last shot.
Pain in adults and older children
Symptoms of difficulty breathing can range from mild to severe. For example:
Certain health conditions and medicines weaken the immune system's ability to fight off infection and
illness. Some examples in adults are:
Shock is a life-threatening condition that may occur quickly
after a sudden illness or injury.
Symptoms of shock in a child may include:
Shock is a life-threatening condition that may quickly occur
after a sudden illness or injury.
Symptoms of shock (most of which will be present) include:
Symptoms of infection may
Many things can affect how your body responds to a symptom and what kind
of care you may need. These include:
Pain in children under 3 years
It can be hard to tell how much pain a baby or toddler is in.
Symptoms of a severe allergic reaction
(anaphylaxis) may include:
A severe reaction can be life-threatening. If you have had a
bad allergic reaction to a substance before and are exposed to it again, treat
any symptoms as an emergency. Even if the symptoms are mild at first, they may
quickly become very severe.
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 more 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 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
should not delay transport for emergency evaluation.
Avoid doing anything
that might cause more problems with the 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.
Call your doctor if any of the following occur during home
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.
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.
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
June 6, 2012
William H. Blahd, Jr., MD, FACEP - Emergency Medicine
& Sean P. Bush, MD, FACEP - Emergency Medicine, Envenomation Specialist
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