Allergies are abnormal immune system
reactions to things that are typically harmless to most people. When a person is allergic
to something, the immune system mistakenly believes that this substance is harming
Substances that cause allergic reactions — such as some foods, dust, plant
pollen, or medicines — are known as allergens.
Allergies are a major cause of illness in the United States. Up to 50 million Americans,
including millions of kids, have some type of allergy. In fact, allergies cause about
2 million missed school days each year.
How Do Allergies Happen?
An allergy happens when the immune system& overreacts to an allergen, treating
it as an invader and trying to fight it off. This causes symptoms that can range from
annoying to serious or even life-threatening.
In an attempt to protect the body, the immune system makes antibodies called immunoglobulin
E (IgE). These antibodies then cause certain cells to release chemicals (including
histamine) into the bloodstream to defend against the allergen "invader."
It's the release of these chemicals that causes allergic reactions. Reactions can
affect the eyes, nose, throat, lungs, skin, and gastrointestinal tract. Future exposure
to that same allergen will trigger this allergic response again.
Some allergies are seasonal and happen only at certain times of the year (like
when pollen counts are high);
others can happen anytime someone comes in contact with an allergen. So, when a person
with a food allergy eats that particular food or someone who's allergic to dust mites
is exposed to them, they will have an allergic reaction.
Who Gets Allergies?
The tendency to develop allergies is often hereditary, which means it can be passed
down through genes from parents to their kids. But just because you, your partner,
or one of your children might have allergies doesn't mean that all of your kids will
definitely get them. And someone usually doesn't inherit a particular allergy,
just the likelihood of having allergies.
Some kids have allergies even if no family member is allergic, and those
who are allergic to one thing are likely to be allergic to others.
What Things Cause Allergies?
Common Airborne Allergens
Some of the most common things people are allergic to are airborne (carried through
Dust mites are microscopic insects that live all around us and
feed on the millions of dead skin cells that fall off our bodies every day. They're
the main allergic component of house dust. Dust mites are present year-round in most
parts of the United States and live in bedding, upholstery, and carpets.
Pollen is a major cause of allergies (a pollen allergy is often
called hay fever
or rose fever). Trees, weeds, and grasses release these tiny particles into the air
to fertilize other plants. Pollen allergies are seasonal, and the type of pollen someone
is allergic to determines when symptoms happen.
measure how much pollen is in the air and can help people with allergies predict how
bad their symptoms might be on any given day. Pollen counts are usually higher in
the morning and on warm, dry, breezy days, and lowest when it's chilly and wet.
Molds are fungi that thrive both indoors and outside in
warm, moist environments. Outdoors, molds can be found in poor drainage areas, such
as in piles of rotting leaves or compost piles. Indoors, molds thrive in dark, poorly
ventilated places such as bathrooms and damp basements. Molds tend to be seasonal,
but some can grow year-round, especially those indoors.
Pet allergens are caused by pet dander (tiny flakes of shed skin)
and animal saliva. When pets lick themselves, the saliva gets on their fur or feathers.
As the saliva dries, protein particles become airborne and work their way into fabrics
in the home. Pet urine also can cause allergies in the same way when it gets on airborne
fur or skin, or when a pet pees in a spot that isn't cleaned.
Cockroaches are also a major household allergen, especially in
inner cities. Exposure to cockroach-infested buildings may be a major cause of the
high rates of asthma in
Common Food Allergens
Up to 2 million, or 8%, of kids in the United States are affected by food
allergies. Eight foods account for most of those: cow's milk, eggs, fish and shellfish,
peanuts and tree nuts, soy, and wheat.
Cow's milk(or cow's milk protein). Between 2% and 3% of children younger than
3 years old are allergic to the proteins found in cow's milk and cow's milk-based
formulas. Most formulas are cow's milk-based. Milk proteins also can be a hidden ingredient
in prepared foods. Many kids outgrow milk allergies.
Egg allergy can be a challenge for parents. Eggs are used in many of the foods kids
eat — and in many cases they're "hidden" ingredients. Kids tend to outgrow egg
allergies as they get older.
Fish and shellfish. These
allergies are some of the more common adult food allergies and ones that people usually
don't outgrow. Fish and shellfish are from different families of food, so having an
allergy to one does not necessarily mean someone will be allergic to the other.
tree nuts. Peanut allergies are on the rise, and as are allergies to
tree nuts, such as almonds, walnuts, pecans, hazelnuts, and cashews. Most people do
not outgrow peanut or tree nut allergies.
Soy allergy is more common among babies than older kids. Many infants who are allergic
to cow's milk are also allergic to the protein in soy formulas. Soy proteins are often
a hidden ingredient in prepared foods.
Wheat proteins are found in many foods, and some are more obvious than others. Although
wheat allergy is often confused with celiac
disease, there is a difference. Celiac disease is a sensitivity to gluten (found
in wheat, rye, and barley). But a wheat allergy can do more than make a person feel
ill — like other food allergies, it also can cause a life-threatening reaction.
Other Common Allergens
For most kids, being stung by
an insect means swelling, redness, and itching at the site of the bite. But for
those with insect venom allergy, an insect sting can cause more serious symptoms.
Medicines. Antibiotics are the most common type of medicines
that cause allergic reactions. Many other others, including over-the-counter medicines
(those you can buy without a prescription), also can cause allergic reactions.
Chemicals. Some cosmetics or laundry detergents can make people
break out in hives. Usually, this
is because someone has a reaction to the chemicals in these products, though it may
not always be an allergic reaction. Dyes, household cleaners, and pesticides used
on lawns or plants also can cause allergic reactions in some people.
Some kids also have what are called cross-reactions. For example,
kids who are allergic to birch pollen might have symptoms when they eat an apple because
that apple is made up of a protein similar to one in the pollen. And for reasons that
aren't clear, people with a latex allergy (found in latex gloves and some kinds of
hospital equipment) are more likely to be allergic to foods like kiwi, chestnuts,
avocados, and bananas.
What Are the Signs and Symptoms of Allergies?
The type and severity of allergy symptoms vary from allergy to allergy and person
to person. Allergies may show up as itchy eyes, sneezing, a stuffy nose, throat tightness,
trouble breathing, vomiting, and even fainting
or passing out.
Kids with severe allergies (such as those to food, medicine, or insect venom) can
be at risk for a sudden, potentially life-threatening allergic reaction called anaphylaxis. Anaphylaxis
can happen just seconds after being exposed to an allergen or not until a few hours
later (if the reaction is from a food).
So doctors will want anyone diagnosed with a life-threatening allergy to carry
an epinephrine auto-injector in case of an emergency. Epinephrine
works quickly against serious allergy symptoms; for example, it reduces swelling and
raises low blood pressure.
Airborne Allergy Symptoms
Airborne allergens can cause something known as allergic rhinitis,
which usually develops by 10 years of age, reaches its peak in the teens or early
twenties, and often disappears between the ages of 40 and 60.
Symptoms can include:
itchy nose and/or throat
When symptoms also include itchy, watery, and/or red eyes, this is called allergic
conjunctivitis. (Dark circles that sometimes show up around the eyes are
called allergic "shiners.")
Food, Medicines, or Insect Allergy Symptoms
itchy, watery, or swollen eyes
a drop in blood pressure, causing lightheadedness or loss of consciousness
Allergic reactions can vary. Sometimes, a person can have a mild reaction that
affects only one body system, like hives on the skin. Other times, the reaction can
be more serious and involve more than one part of the body. A mild reaction in the
past does not mean that future reactions will be mild.
How Are Allergies Diagnosed?
Some allergies are fairly easy to identify but others are less obvious because
they can be similar to other conditions.
If your child has cold-like symptoms lasting longer than a week or two or develops
a "cold" at the same time every year, talk with your doctor, who might diagnose an
allergy and prescribe medicines, or may refer you to an allergist (a
doctor who is an expert in the treatment of allergies) for allergy tests.
To find the cause of an allergy, allergists usually do skin
tests for the most common environmental and food allergens. A skin test can work
in one of two ways:
A drop of a purified liquid form of the allergen is dropped onto the skin and
the area is scratched with a small pricking device.
A small amount of allergen is injected just under the skin. This test stings a
little but isn't painful.
After about 15 minutes, if a lump surrounded by a reddish area (like a mosquito
bite) appears at the site, the test is positive.
Blood tests may be done instead
for kids with skin conditions, those who are on certain medicines, or those who are
very sensitive to a particular allergen.
Even if testing shows an allergy, a child also must have symptoms to be diagnosed
with an allergy. For example, a toddler who has a positive test for dust mites and
sneezes a lot while playing on the floor would be considered allergic to dust mites.
How Are Allergies Treated?
There's no cure for allergies, but symptoms can be managed. The best way to cope
with them is to avoid the allergens. That means that parents
must educate their kids early and often, not only about the allergy itself, but also
about the reactions they can have if they consume or come into contact with the allergen.
Telling all caregivers (childcare staff, teachers, family members, parents of your
child's friends, etc.) about your child's allergy is also important.
If avoiding environmental allergens isn't possible or doesn't help, doctors might
prescribe medicines, including antihistamines, eye drops, and nasal sprays. (Many
of these also are available without a prescription.)
In some cases, doctors recommend allergy
shots (immunotherapy) to help desensitize a person to an allergen. But allergy
shots are only helpful for allergens such as dust, mold, pollens, animals, and insect
stings. They're not used for food allergies.
To help kids avoid airborne allergens:
Keep family pets out of your child's bedroom.
Remove carpets or rugs from your child's room (hard floors don't collect dust
as much as carpets do).
Don't hang heavy drapes and get rid of other items that allow dust to build up.
Clean when your child is not in the room.
Use special covers to seal pillows and mattresses if your child is allergic to
If your child has a pollen allergy, keep the windows closed when pollen season
is at its peak, have your child take a bath or shower and change clothes after being
outdoors, and don't let him or her mow the lawn.
Keep kids who are allergic to mold away from damp areas, such as some
basements, and keep bathrooms and other mold-prone areas clean and dry.
Kids with food allergies must completely avoid products made with their allergens.
This can be tough as allergens are found in many unexpected foods and products.
Always read labels
to see if a packaged food contains your child's allergen. Manufacturers of foods sold
in the United States must state in understandable language whether foods contain any
of the top eight most common allergens. This label requirement makes things a little
easier. But it's important to remember that "safe" foods could become unsafe if food
companies change ingredients, processes, or production locations.
Cross-contamination means that the allergen is not one of the
ingredients in a product, but might have come into contact with it during production
or packaging. Companies are not required to label for cross-contamination risk, though
some voluntarily do so. You may see statements such as "May contain…," "Processed
in a facility that also processes…," or "Manufactured on equipment also used
Because products without such statements also might be cross-contaminated and the
company did not label for it, it's always best to contact the company to see if the
product could contain your child's allergen. Look for this information on the company's
website or email a company representative.
Cross-contamination also can happen at home or in restaurants when kitchen surfaces
or utensils are used for different foods.