Milk, eggs, soy, wheat, tree nuts, peanuts, fish, and shellfish are among the most
common foods that cause allergies.
Young kids who have food allergies often outgrow their allergy — but not always.
A lot depends on which foods someone is allergic to. Some foods are easier to outgrow
than others. Fish and shellfish allergies usually develop later in life, and people
are unlikely to outgrow them.
Food allergies can cause serious and even deadly reactions. So it's important to
know how to recognize an allergic reaction and to be
prepared if one happens.
What Are the Most Common Food Allergens?
Doctors are diagnosing more and more people with food allergies. People can be
allergic to any food, but eight common allergens account for most food allergy reactions:
With a food allergy, the body reacts as though that particular food product is
harmful. As a result, the body's immune
system (which fights infection and disease) creates antibodies to fight the food
Every time the person eats (or, in some cases, handles or breathes in) the food,
the body releases chemicals like
. This triggers allergic symptoms that can include:
a drop in blood pressure, causing lightheadedness or loss of consciousness (passing
People often confuse food allergies with food intolerance because
of similar symptoms. The symptoms of food intolerance can include burping, indigestion,
gas, loose stools, headaches, nervousness, or a feeling of being "flushed."
But food intolerance:
doesn't involve the immune system
can happen because a person can't digest a substance, such as lactose
can be unpleasant but is rarely dangerous
What Happens in a Food Allergy Reaction?
Most reactions happen pretty soon after eating a particular food. Everyone's different,
though. So although two people may have peanut allergy, for example, both may not
have the same type of allergic reaction. And even the same person can have different
reactions to a particular food, depending on factors like how much he or she was exposed
be very mild and only involve one part of the body, like hives on the skin
be more severe and involve more than one part of the body
happen within a few minutes or up to 2 hours after contact with the food
Food allergy reactions can affect any of these four areas of the body:
skin: itchy red bumps (hives); eczema;
redness and swelling of the face or extremities; itching and swelling of the lips,
tongue, or mouth (skin reactions are the most common type of reaction)
Sometimes, an allergy can cause a severe reaction called anaphylaxis,
even if a previous reaction was mild. Anaphylaxis might start with some of the same
symptoms as a less severe reaction, but can quickly get worse. The person may have
trouble breathing or pass out. More than one part of the body might be involved. If
it isn't treated, anaphylaxis can be life-threatening.
How Is a Food Allergy Diagnosed?
Your doctor will look for any other conditions that could be causing symptoms.
For example, if you have diarrhea after drinking milk, the doctor may check to see
if lactose intolerance
could be causing the problem instead of a food allergy. Another condition that may
mimic food allergy symptoms is celiac
disease. People with celiac disease are not able to tolerate gluten, a protein
found in wheat and certain other grains.
If your doctor thinks you have a food allergy, you'll probably see an
. The allergist will ask you questions again and do a physical exam (such
as listening to your lungs). He or she will probably also run
some tests to help diagnose the problem.
The most common kind of allergy test is a skin test. A doctor
or nurse will scratch the skin (usually on the forearm or back) with a tiny bit of
the extract, then wait a few minutes to see if there's a reaction. Doctors may also
do other tests, including a blood
test. Blood tests show if there are antibodies to a particular food in the person's
If you do have a food allergy, your allergist will work with you to create a treatment
plan. You'll also develop a written food allergy emergency action plan to keep at
school to help you avoid a serious reaction — and to provide guidance in case you
do have a reaction.
How Are Food Allergies Treated?
There's no cure for food allergies, and the only real way to treat them is to avoid
the food in question. But doctors can prescribe medicines to help lessen symptoms
if they do happen, and even save a person's life if the reaction is serious.
Antihistamines can treat isolated symptoms such as hives, runny nose, or abdominal
pain associated with an allergic reaction.
If your doctor diagnoses you with severe allergies, he or she may prescribe epinephrine,
which can be lifesaving if a person has anaphylaxis. Because it's important that the
medicine get into a person's bloodstream quickly, epinephrine comes in an auto-injector.
If your doctor has prescribed epinephrine, you'll need to take the auto-injector
with you everywhere you go and also keep one on hand at home, school, and any relatives'
or friends' homes that you visit a lot.
So how do you know when you should use epinephrine? Your doctor will go over this
with you, but signs and symptoms of anaphylaxis include:
throat feels tight
swelling in the mouth
any symptoms from two or more body systems (skin, heart, lungs, etc.), such as
hives and belly pain
any other combination of two or more symptoms that affect different parts of the
If you have to give yourself a shot of epinephrine (or someone else gives it to
you), call 911 immediately after so an ambulance can take you to
the hospital. This is important because sometimes there can be a second wave of symptoms.
Medical staff need to watch anyone who has used epinephrine for a severe allergy in
case the person needs more treatment.
Avoiding Food Allergens
If you have food allergies of any kind, you'll become an expert in reading food
Makers of foods sold in the United States must state whether foods contain any
of the top eight most common allergens: milk, eggs, fish, shellfish, tree nuts, peanuts,
wheat, or soy.
Label information helps if you're buying packaged foods, but what about when you
eat away from home? If you have a food allergy, tell the people serving you know about
it. Most of the time, you can't stop there: Ask what each food on a menu or in the
display case contains. If the people helping you don't know, see if they can find
out (from the chef or person who prepared the food).
You'll also need to be aware of other food pitfalls, such as the possibility that
the food you're allergic to could get into other items from cutting surfaces, shared
a food allergy can be hard. If you know someone with food allergy, show your support
and understanding. Some people with food allergies may feel left out or awkward. And
if you have a food allergy, let your friends know. Chances are, they'll understand
and look out for you.