FOOD ALLERGIES
Reactions to food are common. These reactions range from
mild to severe, and may result from your body's negative
response to certain foods or from a true food allergy.
Any food can cause an allergic reaction, but only eight
foods cause nine out of ten reactions. They are milk,
soy, eggs, wheat, peanuts, tree nuts, fish and
shellfish.
What is a Food Allergy?
Who Gets a Food Allergy?
What are the Symptoms?
What are Some Tips to Follow to Prevent an
Allergic Reaction?
What Can Do If I Have a Reaction?
INHALANT
ALLERGIES
Inhalant allergens are those airborne particles which
may cause your asthma and/or allergy symptoms to appear.
When you breathe in something you are allergic to, a
reaction is likely to occur. Inhalant allergens include
animals, dust mites, cockroaches, mold, and pollen.
Hay Fever
Animal Allergens
Dust Mites
Molds
Pollens
What is a
Food Allergy?
The job of immune system cells is to find foreign
substances such as viruses and bacteria and get rid of
them. Normally, this response protects us from dangerous
diseases. People with food allergies have
super-sensitive immune systems that react to harmless
substances found in food and drink. These substances are
called allergens. When people have an allergy, there are
antibodies to the allergens in their blood and
throughout their body. When that person eats a food to
which they are allergic, the food allergens react to
antibodies on cells releasing chemicals.
Who Gets a
Food Allergy?
From 3 percent to 8 percent of children have reactions
to some foods. Only 1 percent to 2 percent have true
food allergies. Some children seem to grow out of their
sensitivity to certain foods, often by age 4. Allergies
to peanuts, tree nuts and shellfish usually do not go
away, though.
From 1 percent to 2 percent of adults have true food
allergies. But people of any age can have sudden
allergic reactions to a food that had previously not
been a problem for them.
If you have an allergy, a reaction is triggered within
minutes to two hours after you consume the allergen. How
soon and how severe the reaction is depends on how
sensitive you are to the food, the amount of the food
consumed, other food consumed, the manner in which it is
prepared (i.e., cooked or uncooked, seasoned or
unseasoned), and any other medical problems you have.
Severe, life-threatening reactions are more common with
allergies to peanuts, tree nuts, shellfish, fish and
eggs. These life-threatening reactions are more common
in people who also have asthma.
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What are the
Symptoms?
Reactions can affect different body systems:
The digestive tract, which first comes into contact with
food. Some symptoms, such as swelling and itching of the
lips, the lining of the mouth as well as throat
tightness and hoarseness may occur quickly. When the
food enters the stomach and then the intestines, nausea,
cramping, pain, vomiting and diarrhea may occur.
Body systems, such as the skin, lungs and blood vessels,
that are affected after the food leaves the digestive
tract. These reactions can occur in minutes or within
two hours. Often, hives and swelling of the skin occur.
Anaphylaxis, the most dangerous and life-threatening
result of a food allergy, usually occurs within minutes
after consuming the food. When this happens, blood
vessels widen so much that blood pressure falls.
Symptoms include wheezing, difficulty breathing, throat
tightness, nausea, rapid pulse, flushing, faintness,
itching of the palms and sole of the feet and even
passing out. Without speedy treatment, this intense
allergic reaction can cause death. (See the Asthma and
Allergy Answers factsheet, "What is Anaphylaxis").
The first severe reaction to a food may be unexpected.
Sometimes the patient may at first have minor symptoms
such as stomach cramping or hives.
What Can Be Done to Avoid Developing Food Allergies?
To prevent or modify the development of food allergy,
identify early in life people who are most at risk:
Those with a family history of allergy
Babies with allergy antibodies in their umbilical cord
blood or serum
Infants less than 12 months old with antibodies to egg
and other foods including peanut, codfish and milk
Consult a doctor about whether to test an infant for
allergy antibodies. If positive, talk with the doctor
about how to decrease the incidence and severity of the
food allergy.
Allergic reactions to cow's milk or soy formula can
appear within days or months after birth. There is
evidence that infants who are breast-fed exclusively
during their first six to 12 months of life develop
fewer allergies by age one or two than infants fed with
formula. The American Academy of Pediatrics (AAP)
recommends exclusive breast-feeding as ideal nutrition
for about the first six months of life. Furthermore, a
maternal diet that avoids eggs, cow milk, peanuts and
fish while nursing may help reduce eczema in infants.
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What are
Some Tips to Follow to Prevent an Allergic Reaction?
Do not consume foods that cause a reaction. People with
a severe allergy can go into anaphylactic shock from
trace amounts of the food to which they are allergic.
Touching foods cause some people to have a severe
reaction.
Read the ingredients lists on food labels to make sure
allergy-causing foods are not mixed in. Read the list
even if you have had the product before. Ingredients may
change.
If you are traveling, send special foods ahead. Stay in
hotels with kitchenettes so you can prepare your own
food.
When eating out, always ask restaurant staff about
ingredients in food and how it was prepared. Cooking
oils can have allergens. Peanut oil is often used in
cooking, particularly in Thai cuisine.
For infants, elemental formulas or formulas with altered
protein should prevent food reactions. Discuss the
various formula options with your doctor. Do not assume
products labeled "hypoallergenic" will not cause a
reaction.
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What Can Do
If I Have a Reaction?
If you have a severe reaction, take medication and seek
medical care promptly. Injectable epinephrine, such as
EpiPen or Ana-Kit, should always be at hand for treating
anaphylactic shock. Get medical care promptly after
using epinephrine, even if you feel better. Symptoms may
reoccur in a few hours.
Antihistamines and steroids also may be taken to lessen
symptoms. Prompt treatment often can limit the severity
of the reaction. If you have life-threatening allergies,
wear a Medic-Alert bracelet to let health care workers
know of your allergy in an emergency.
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Hay Fever
The classic example of inhalant allergy is hay fever -
this may cause itchy conjunctivitis (the white of the
eye may have a cobblestone appearance) with redness and
watering. In the nose there is rhinitis with thin clear
secretions and sneezing. There may also be blockage and
loss of the sense of smell with sinusitis. Pollen in the
nose, mouth and throat may cause itching, in the lungs,
asthma.
These effects are all mediated by the release of
histamine. Conventional treatment of hay fever is about
symptoms suppression with antihistamines (block the
effect of histamine), sodium cromoglycate (stabilises
the allergy cells) and steroid sprays or tablets (these
turn off all immune reactions good and bad).
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Animal
Allergens
While pets are wonderful additions to a household, they
can cause allergic reactions in those who are sensitized
to animal allergens. The most common animal allergies
are to cats and dogs, but any warm-blooded pet including
small rodents, birds, rabbits, cows, and horses can
cause problems.
Most animal allergens circulate throughout a house as
small microscopic particles, invisible to the human eye.
Cat allergen, for example, can come from the saliva,
fur, body secretions, or skin and is only about two
microns. As a comparison, the cross section of a human
hair is 100 microns. Regular resting sites of animals
like carpets, couches, and beds generally have a
significant allergen build-up.
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Dust Mites
Dust mites are tiny microscopic creatures that cause
allergic reactions. These hardy creatures like to live
in warm, humid places and are found in most areas of the
United States. They thrive in temperatures from 72 to 80
degrees Fahrenheit with humidity levels of 75 to 80
percent. They die when the humidity falls below 40 to 50
percent, so they are rarely found in dry climates.
It is nearly impossible to avoid dust mites as they are
found in even the cleanest houses.
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Mold
Warm
temperatures and humidity may be great for plants, but
they can play havoc with your allergies if you are
sensitized to them. Molds are most prevalent during the
summer months, but can be a year-round hazard in warmer
zones. In some areas, high mold counts occur at the same
time of year as high pollen counts. This can make the
spring and fall allergy seasons especially difficult for
those who are sensitized to those allergens.
You don't have to go outside to be affected by molds
though. Mold can thrive indoors in your heating/cooling
system, in the basement, and in the bathroom.
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Pollen
If your asthma or
allergy symptoms flare up only at certain times of the
year, you may be allergic to pollen. One out of five
people in the United States suffer from pollen-related
hay fever.
Pollen is tiny, seed-like grains released by flowers,
trees, grasses, and weeds in order for these plants to
reproduce. These grains are carried by the wind or
insects and can travel for hundreds of miles. (A square
mile of ragweed, one of the top pollen producers, lets
out up to 16 tons of pollen, and can be blown up to 100
miles away!) Wind-borne pollen can easily get into your
eyes, nose, or airways causing havoc to your system.
Insect borne pollen generally is too large to cause an
allergic response. For this reason trees that flower
like dogwoods don't cause allergies.
Tree pollen is prevalent in early spring; grass pollen
is present from late spring through mid-summer in the
Midwest, and longer in the Southern states; ragweed, as
well as other weeds, pollinates in late summer and up
until the first hard frost in the Midwest.
While there is no way to eliminate pollen from the air,
the following may help in reducing your symptoms when
pollen counts are especially high.
•
Check the local pollen
count daily. When counts are high, avoid outdoor
activities.
•
Keep your house closed
during the pollen season.
•
Use central air
conditioning when possible. Leave the fan on so to
continuously circulate the inside air through the
filters (use extended surface multi-pleat filters if you
need disposable filters).
•
Do not use an attic fan
during pollen season. It draws outside, pollen-filled
air into the house.
•
Avoid outdoor exposure
during midday and early afternoon when pollen counts are
highest.
•
Save outdoor activities
for after a rain when pollen has been washed out of the
air, but be aware that some molds only release their
spores into the air on rainy days or when the humidity
is high.
•
Wear glasses to avoid
getting pollen in your eyes.
•
After being outdoors,
shower and wash your hair, change your clothes, and
place dirty clothes in a hamper outside the bedroom.
•
Wear a mask when doing
yard work. It's best not to work outdoors during your
particular "season", if you are allergic to pollens or
mold.
•
Avoid using sedating
antihistamines in you are operating machinery or driving
your car.
•
Make sure you take your
allergy injections regularly. |
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