Overview
What is a peanut allergy?
A peanut allergy is a
reaction that occurs when your body mistakenly identifies peanuts as harmful
substances. When you eat peanuts or food containing peanuts, your
immune system—the body's natural defense system that
fights infections and diseases—overreacts and can cause a serious, even
life-threatening response.
What causes a peanut allergy?
An
allergic reaction occurs when your immune system
overreacts and releases chemicals, including histamine, into your blood. These
chemicals can affect different tissues in the body, such as the skin, eyes,
nose, airways, intestinal tract, lungs, and blood vessels. It's not clear why
peanuts trigger this response in some people.
What are the symptoms?
Symptoms of peanut allergy
can range from mild to life-threatening. If you have a mild reaction, you may
get a stomachache, a runny nose, an itchy skin rash,
hives, or tingling in your lips or tongue. If your
reaction is worse, you may develop additional symptoms such as a tight throat,
hoarse voice, wheezing, coughing, feeling sick to your stomach, vomiting, belly
pain, and diarrhea. Your symptoms may start from within a few minutes to a few
hours after eating peanuts or peanut products.
People who are
allergic to peanuts may have a life-threatening reaction called
anaphylaxis. Symptoms of anaphylaxis can include
difficulty breathing and swallowing, vomiting and diarrhea, dizziness,
dangerously low blood pressure, swelling of the lips, tongue, throat, and other
parts of the body, and loss of consciousness. If not treated, death can result.
Anaphylaxis usually occurs within minutes but can occur up to several hours
after eating peanuts or peanut products.
How is a peanut allergy diagnosed?
Your doctor or
allergy specialist will ask you about your previous reactions to peanuts or
peanut products, such as how long it took to develop symptoms after eating
peanuts, and whether any of your family members have allergies or conditions
like
asthma. Next, the allergy specialist will do a skin
test to see if you have an allergic reaction. During a skin test, a tiny bit of
your skin will be pricked and a small amount of peanut liquid will be placed on
your skin. If you develop a skin rash or red bumps in that area of your skin,
it is likely you are allergic to peanuts.
You may also need to
have a blood test that will show whether your body has made
proteins called
antibodies that would cause an allergic reaction when
you eat peanuts. One such test is called an ELISA test, and another is called a
RAST test.
How is it treated?
If you accidentally eat a
peanut, follow your doctor's instructions. For a mild reaction, you may only
need to take an
antihistamine, such as diphenhydramine hydrochloride
(Benadryl), to reduce your symptoms of a runny nose or itchy skin.
If your allergic reaction is more severe, be sure to follow your doctor's
instructions for this type of reaction. If you have had a severe reaction
previously, your doctor has probably prescribed a medicine called
epinephrine. Give yourself the epinephrine shot, take
an antihistamine, and call 911 for further
instructions.
For more information on how to give an epinephrine
shot, see:
Allergies: Giving yourself an epinephrine shot.- Allergies in children: Giving an epinephrine shot to a child.
Even if you feel better after giving yourself the shot,
symptoms of anaphylaxis can recur or suddenly appear hours later. You need to
be observed in a hospital for several hours after your symptoms go away.
If you do not have epinephrine and are having a severe allergic
reaction, call 911 immediately.
How can I avoid an allergic reaction?
To prevent
an allergic reaction to peanuts:
- Understand your allergy and know that you
need to protect yourself. Read food labels or ask kitchen staff at restaurants
if there are peanuts or peanut oils hidden in any of the foods you order. For
example, some cooks thicken chili with peanut butter.
- Understand
that no amount of peanut is safe. Some people are so severely allergic to
peanuts that being near them or breathing air that contains peanut residue can
cause an allergic reaction.
- Let others know that you or your child
has a peanut allergy. Make sure that all caregivers (such as school
administrators, teachers, babysitters, and coaches), friends, and coworkers:
- Know what the symptoms of an allergic
reaction look like.
- Know where the epinephrine shot is kept and how
to give the shot.
- Have a plan to transport you or your child to the
hospital.
- Wear a
medical alert bracelet or medallion that lists your peanut allergy. This will
alert emergency response workers if you have a severe allergic reaction.
Medical alert jewelry can be ordered through most pharmacies or on the
Internet.
- Keep your epinephrine shot with you at all times. Make
sure older children know how to give you or themselves the shot. Talk with your
doctor or pharmacist if you are unsure how to give yourself the
shot.
- Keep an antihistamine such as diphenhydramine hydrochloride
(Benadryl) with you at all times. These medicines can be used in addition to
epinephrine and are often helpful in both mild and severe allergic
reactions.
If you think you are having an allergic reaction:
- Get help. Do not minimize the seriousness of the
problem.
- After you give yourself an epinephrine shot, call your
doctor immediately or seek other emergency services. You will need to be
observed for several hours to make sure the reaction does not recur.