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
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.
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
problems 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.
To diagnose a
peanut allergy, your doctor will start with a
medical history and a physical exam. Your doctor will
ask about any family food allergies, especially siblings with peanut allergies. He or she will ask detailed questions
about your symptoms, how soon your symptoms began after you ate the food, and if any over-the-counter allergy medicines like an antihistamine were helpful. Your doctor will ask if other people also got sick, how the food was prepared, and what other foods were eaten.
It's important to find out whether you have a
food allergy or food intolerance. Your doctor may ask you to keep a record of
all the foods you eat and any reactions to the foods. Your doctor will also consider if your reaction could have been caused by things like allergies to medicines or insect stings, food poisoning, irritants in foods, and exposure to skin irritants.
Your doctor may ask you
to try an elimination diet, an oral food allergy challenge, or both.
You may also have
allergy tests, such as skin tests or blood tests, to determine what foods you are allergic to after you have been diagnosed with having a food allergy.
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
For more information on how to give an epinephrine
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.
an allergic reaction to peanuts:
If you think you are having an allergic reaction:
March 9, 2011
Sarah Marshall, MD - Family Medicine & Rohit K Katial, MD - Allergy and Immunology
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