Food Allergy:   

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 Allergy: 

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 Intolerance: 

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.

Understanding Allergic Reactions: 

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 your:

  Nose

  Throat

  Lungs

  Skin

  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 with allergies.

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 reaction: 

  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
     histamine.  

  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 reactions. 

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 example: 

  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 or eczema.  

  When the allergens reach your lungs, they may cause asthma.  

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 shellfish

  Peanuts (one of the chief foods responsible for severe anaphylaxis)

  Walnuts and other tree nuts

  Fish

  Eggs

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 outgrown.

Adults usually do not lose their food allergies.