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Allergies Health Center

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Food Allergies

A food allergy occurs when your immune system responds defensively to a specific food protein that is not harmful to the body.

The first time you eat the offending food, your immune system responds by creating specific disease-fighting antibodies (called immunoglobulin E or IgE). When you eat the food again, the IgE antibodies spring into action, releasing large amounts of histamine in an effort to expel the "foreign invader" from your body. Histamine is a powerful chemical that can affect the respiratory system, gastrointestinal tract, skin or cardiovascular system.

Night Terrors in Children

Night terrors are distinctly different from the much more common nightmares, which occur during REM sleep. Night terrors are characterized by frequent recurrent episodes of intense crying and fear during sleep, with difficulty arousing the child. Night terrors are frightening episodes that disrupt family life.

An estimated 1-6% of children experience night terrors. Boys and girls are equally affected. Children of all races also seem to be affected equally. The disorder usually resolves during adolescence.

What Are the Symptoms of a Food Allergy?

Symptoms may appear almost immediately, or up to two hours after you've eaten the food. Symptoms can include a tingling sensation of the mouth, swelling of the tongue and throat, hives, skin rashes, vomiting, abdominal cramps, difficulty breathing, diarrhea, a drop in blood pressure, or even a loss of consciousness. Severe reactions -- called anaphylaxis -- can result in death.

Some individuals can develop a rash in areas that come in contact with foods. There are people who are so sensitive to food allergens that the odor of that particular food can cause a reaction.

Which Foods Most Often Cause Allergic Reactions?

The most common food allergies are reactions to milk, eggs, peanuts, seafood, and tree nuts (such as walnuts, pecans, almonds, pine nuts, and Brazil nuts).

How Are Food Allergies Diagnosed?

By keeping a food diary, your doctor will have a much better starting point to determine the foods that could trigger your allergies.

Your doctor may recommend a food elimination diet where you may be asked to eliminate one or several potentially allergenic foods to see if the reaction goes away,

Oral food challenges -- exposing the person to the suspected food under medical supervision -- are thought to be helpful as well. These are usually done after the elimination diet.

Your doctor may do a radioallergosorbent blood test (RAST) to check the number of antibodies produced by your immune system. Elevated levels of certain types of antibodies can help your doctor identify specific food allergies.

The doctor may also perform an allergy skin test, also called a scratch test, to identify the substances that are causing your allergy symptoms.

Some food allergies are very subtle, and in difficult to diagnose situations, a new approach is to look at IgG antibodies related to foods. More data and experience are needed, but this is a promising aid when symptoms are more subtle and make it difficult to figure out the cause. In addition, there are now genetic tests, especially for gluten and celiac (wheat, barley, rye and some oats).

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