Overview Of Allergy To Food
A food allergy is an immune overreaction that is triggered by a specific food product. Common examples include peanuts, eggs, and shellfish.
Commonly Associated With
Peanut allergy, soy allergy, fish allergy, shellfish allergy, egg allergy, and milk allergy
Causes Of Allergy To Food
A lot of people have a food intolerance, instead of a true allergy. Food intolerance symptoms usually include stomach cramps, heartburn, abdominal pain, or diarrhea. Common foods that can cause this reaction include:
- Wheat and other gluten-containing grains (celiac disease)
- Cow’s milk and related dairy products (lactose intolerance)
- Various corn-based products
A true food allergy is much less common than a food intolerance. Food allergies come about because of an overreaction of the immune system.
The immune system normally functions to protect the body against truly harmful things, such as viruses, bacteria, and fungi. But in some cases it can also react to allergens, which are normally harmless foreign substances.
In those with food allergies, their immune system is oversensitive, and it will react violently whenever it senses a particular allergen (food products, in this case). Chemicals released during this process, called histamines, cause many different allergy symptoms.
Any food product can cause an allergic reaction – it mostly depends on the person eating it. The most common foods to cause allergic reactions are:
- Peanuts (all ages)
- Wheat (all ages)
- Shellfish such as crab, shrimp, and lobster (all ages)
- Milk (all ages)
- Tree nuts (all ages)
- Fish (older children and adults)
- Eggs (mostly children)
- Soy (mostly children)
In rare instances, food additives can cause an allergy or food intolerance reaction. For example, thickeners, dyes, and preservatives can cause intolerance reactions.
Some people’s allergic reaction symptoms are only in their oral area. This type of allergy specifically affects the mouth and tongue, and only after the person eats particular fruits or vegetables. Apples, pineapples, and melons can cause these types of reactions. These fruits in particular contain substances that are similar to certain pollens, which people can also have an allergic reaction to, perhaps explaining the reaction.
Eating the raw form of the food most often triggers a reaction. However, the severity of the reaction depends on the amount of the food the person ate, and how reactive their system is to that particular food.
Symptoms Of Allergy To Food
Most allergy symptoms emerge within 2 hours of the food being eaten. But in some cases, the symptoms may take hours to appear.
The main symptoms of a food allergy reaction are wheezing, hives, and a hoarse voice.
Other possible symptoms include:
- Angioedema (swelling), especially on the face, lips, eyelids, and tongue
- Difficulty breathing or swallowing due to throat swelling
- Diarrhea, nausea, stomach cramps, or vomiting
- Fainting or lightheadedness
- Nasal congestion or a runny nose
- Itching of the throat, eyes, mouth, skin, or any other area of the body
Exams & Tests
Blood and skin tests can confirm food allergies in people. In other cases, health care providers may use a double-blind food challenge. In this test, both the provider and the patient won’t know which samples contain the allergen and which don’t.
An elimination diet is another possible diagnostic method. The person can avoid their suspected food allergen for a set length of time, and then reintroduce the food into their diet to see if they develop an allergic reaction.
With challenge/provocation testing, the patient eats a small amount of their suspected food allergen, with medical supervision. This type of test is usually used for severe allergic reactions, and should only be conducted by a health care provider.
Patients should never attempt to cause an allergic reaction or reintroduce a food into their diet on their own. These types of tests should only be done with the permission and supervision of a health care provider.
Treatment Of Allergy To Food
If a person or their child has a suspected food allergy, they should be sure to see an allergist (doctor that specializes in allergies) immediately.
Various treatments can include any of the following:
- Completely avoiding the food allergen that causes the reaction. This is the most effective treatment for allergies.
- Desensitization treatments. This means that the person will eat small amounts of the food allergen every day, in an attempt to stop their immune system from overreacting every time. This needs to be done under the supervision of an allergist.
- For mild food allergies, treatment may not be needed, other than some antihistamine medication. The symptoms will most likely fade on their own with time.
- Soy-based formula or an “elemental formula” may be used for infants who have an allergy to cow’s milk.
- Food allergies do not usually respond to probiotics or allergy shots.
Those with food allergies need to know how to use injectable epinephrine. They should have it with them at all times. If any type of reaction develops, they should inject the epinephrine, then go to the nearest hospital as soon as possible, preferably by ambulance if possible.