Definition & Overview

At least one in every five Americans has an allergy and more than 50% of the population has been diagnosed to be allergic to at least one allergen. This makes allergies one of the top five chronic diseases in the country.

Meanwhile, about fifteen million of Americans, including children, have a food allergy. This is an allergic reaction to a component of food, usually its protein, and/or its derivatives (e.g., corn syrup), as well as preservatives such as potassium sulphites and monosodium glutamate (MSG).

Over the last few years, the number of emergency admissions due to food allergies among children has increased to about 50%, although experts are still trying to find out the reason why. Some assumed that the diet has changed considerably over that period.

Causes of Condition

An allergy is actually the body’s natural response to threats. Our bodies have a built-in immune system made up of white blood cells and antibodies that fight off any type of threat that may lead to infection.

An allergy develops when the immune system mistakes the proteins of certain types of food or their derivatives as a potential threat. When it recognizes these as threats, antibodies called immunoglobulin E (IgE) instruct the immune system to release certain chemicals such as histamine.

As soon as histamine is released, the person then develops the signs and symptoms of allergies. The blood vessels especially those on the surface of the skin dilate and begin to swell, nerves become more sensitive, and lining of the nose produces more mucus.

Food allergies may be divided into two types: non-IgE-mediated and IgE-mediated. Unlike the latter, which is caused by a certain immunoglobulin, the former is believed to be mediated by T cells. These are white blood cells that look for and destroy threats. Non-IgE-mediated is less studied and is therefore not easily diagnosed by doctors. However, it is more common among children and is characterized by a delayed onset of symptoms, such as 28 hours after digestion.

Some of the most common triggers of food allergies are:

  • Eggs
  • Milk
  • Chocolate
  • Wheat
  • Peanuts
  • Fish
  • Corn
  • Gluten (a kind of protein found in certain types of wheat and grains like rye and barley)
  • Meat especially chicken

Aside from being an immunological response, there’s no other solid explanation for allergies. However, the risks are higher if you have a family history or you have been diagnosed with an allergic condition before such as eczema or asthma.

Key Symptoms

  • Skin rash or swelling
  • Watery or swollen eyes
  • Running nose
  • Itchiness around the mouth or the lips
  • Itchiness of the skin
  • Bloating, abdominal pain, and stomach cramps
  • Diarrhea
  • Vomiting and nausea
  • Headache
  • Stomach pain
  • Asthma
  • Sneezing

An allergic reaction is normally easy and quick to treat, but it may be an emergency when the patient develops anaphylaxis, a severe allergic reaction. A person with anaphylaxis may experience these symptoms within 5 minutes to 2 hours of digestion:

  • Anxiety
  • Loss of consciousness
  • Lightheadedness or dizziness
  • Confusion
  • Difficulty of breathing
  • Skin flushing
  • Severe abdominal cramps
  • Irregular heart rate
  • Low blood pressure
  • Difficulty in swallowing
  • Incontinence

Anaphylaxis can lead to shock and, therefore, can be fatal.

Who to See and Treatments Available

While a general doctor is capable of treating food allergies, the best practitioner to approach is an allergist or an allergy specialist. This doctor can perform a variety of tests to help determine the trigger of the allergies. These include blood and/or skin prick tests. Both of these examinations are meant to determine the levels of immunoglobulin E in your system.

In the skin prick test, the allergist places a small amount of solution containing the potential allergy trigger and scratches the skin’s surface to allow extensive penetration of the solution. The doctor then observes the reaction of the skin. If the skin develops a wheal, then most likely you are allergic to the food.

Although this test is quick—you can see results within 30 minutes—it’s not accurate all the time, so the allergist may decide to complement it with a blood test.

If none of these tests will satisfy the allergist, then the patient may undergo an oral food challenge. The patient needs to eat the food gradually while the doctor observes for any allergic reaction. Due to the possible severity of the reaction, this should be conducted in a health care facility and by an allergist only.

As for treatments, the allergist may recommend:

  • Epinephrine: Also referred to as the EpiPen, it’s the only treatment available for severe allergic reactions like anaphylaxis. Patients may administer it themselves by injecting it into their thighs. This delays or reverses the symptoms, although patients still need to be brought to the hospital for proper treatment.

  • Antihistamines: As their name suggests, they block the release of histamines into the bloodstream. Some of the most popular types of antihistamines are Benadryl and Claritin. They are ideal for mild allergic reactions.

  • Steroids: Steroids can be used to suppress the overactive immune system and reduce the inflammation of the body. They are often provided by health care facilities upon admission of the patient.

When a person develops asthmatic tendencies during a food allergy, he may take medications like Ventolin or Proventil.

  • Food and allergy diary: The allergist may also encourage you to keep a diary of the food you’ve eaten and allergic reactions. They can be handy when you’re trying to determine the exact cause of your allergy or when the allergist performs an elimination diet.

There’s no cure to allergies yet though some have proven to be responsive to desensitization. Also referred to as immunotherapy, it’s a process where allergens are introduced gradually, normally over a period of years, to the patient so the immune system no longer reacts to it.

Desensitization, however, works best in allergies caused by insect stings, as well as severe hay fever. Food allergy desensitization is still a work in progress.

In the meantime, the best way to prevent food allergy is to have yourself tested for the triggers and avoid them.

References:

  • http://acaai.org/allergies/types/food-allergies/types-food-allergy/corn-allergy
  • http://www.nhs.uk/Conditions/food-allergy/Pages/Causes.aspx
  • http://www.foodallergy.org/diagnosis-and-testing
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