An allergy to food is an abnormal response, triggered by the body's
immune system. Symptoms can include itching in the mouth, vomiting, hives, and asthma.
In some cases, the reaction can be so severe that it causes serious illness, or even death. Sometimes people
suspect an allergy, when in fact they are experiencing another type of reaction called food intolerance.
Treatment usually involves avoiding the food that triggers the allergic reaction.
What Is a Food
Food allergy affects up to 6 to 8
percent of children under the age of three, and
2 percent of adults. Approximately 30,000 people require emergency room treatment and 150 Americans die each year
because of allergic reactions to food.
If you have an unpleasant reaction to
something you have eaten, you might wonder if you have a food allergy. One out of three people either believe
they have a food allergy or modify their or their family's diet because of this belief.
Food Allergy or Food
A food allergy is an abnormal response
to a food triggered by the body's immune system. These allergic reactions can cause serious illness and, in some
cases, death. Therefore, if you have a food allergy, it is extremely important for you to work with your
healthcare provider to find out what food(s) could be causing your allergic reaction.
If you go to your healthcare provider
and say, "I think I have a food allergy," your healthcare provider has to consider other possibilities that may
cause symptoms and could be confused with food allergy, such as food intolerance.
To find out the difference between food allergy and food intolerance, Dr. Hardy will go through a list of
possible causes for your symptoms. This is called a differential diagnosis. This type of diagnosis helps confirm
that you do indeed have a food allergy rather than an intolerance or other illness.
Food intolerance is more common than a
food allergy. The immune system does not cause the symptoms of food intolerance, though these symptoms can look
and feel like those of an allergy.
An immediate allergic reaction involves
two actions of your immune system.
Your immune system produces immunoglobulin E (IgE), a type of protein that works against a specific food. This
protein is called a food-specific antibody,
and it circulates through the blood.
The food-specific IgE then attaches to
mast cells, which are found in all body tissues. They are more often found in areas of your body that are
typical sites of allergic reactions.
Those sites include
Gastrointestinal (GI) tract.
Generally, your immune system will form
IgE against a food if you come from a family in which allergies are common -- not necessarily food allergies,
but perhaps other allergic diseases, such as hay fever or asthma.
If both of your parents have allergies, you are more likely to develop a food allergy than someone with one parent
If your immune system is inclined to form IgE to certain foods, you must be exposed
to the food before you can have an allergic reaction. This is what happens in a typical allergic
As the specific food is digested, it triggers certain
cells in your body to produce
a food-specific IgE in large amounts. The food-specific IgE is then released and
attaches to the surfaces of mast cells.
The next time you eat that food, it interacts with
food-specific IgE on the
surface of the mast cells and triggers the cells to release chemicals such as
Depending upon the tissue in which they are released,
these chemicals will
cause you to have various food allergy symptoms.
Food allergens are proteins within the food that enter your bloodstream after the
food is digested. From there, they go to target organs, such as your skin or nose, and cause allergic
An allergic reaction to food can take place from within a few minutes up to an hour.
The process of eating and digesting food affects the timing and the location of a reaction. For
If you are allergic to a particular food, you may
first feel itching in your mouth
as you start to eat the food.
After the food is digested in your stomach, you may
have GI symptoms, such
as vomiting, diarrhea, or pain.
When the food allergens enter and travel through your
bloodstream, they may
cause your blood pressure to drop.
As the allergens reach your skin, they can cause hives
When the allergens reach your lungs, they may cause
Common Causes of Food Allergy:
Food allergy patterns in adults differ
somewhat from those in children.
The most common foods to cause allergies in adults are:
Shrimp, lobster, crab, and other
Peanuts (one of the chief foods responsible for severe
Walnuts and other tree nuts
In children, eggs, milk, peanuts, soy,
and wheat are the main culprits.
Children typically outgrow their food
allergy to milk, egg, soy, and wheat, while allergies to peanuts, tree nuts, fish, and shrimp usually are not
Adults usually do not lose their food allergies.