What Causes Food Allergies?

Roughly 32 million Americans suffer from food allergies. Of these, 5.6 million are children under the age of 18. (Food Allergy Research & Education, n.d.)

Many children are allergic to more than one food. Some of the most common food allergies include peanut allergy and cow's milk allergy. The prevalence of food allergies is on the rise.

Food allergies severely impact a person's quality of life. Sometimes, the ingestion, inhalation, or contact with the allergen may cause a severe, life-threatening allergic reaction. Children with a food allergy are more likely to have other conditions related to allergies such as eczema and asthma.

What is a Food Allergy?

A food allergy is a reaction involving the immune system. This reaction occurs shortly after eating a particular food. In some cases, inhalation of a substance or contact with it can also cause a reaction. Even a minimal amount of the allergen can cause symptoms.

There is no cure for food allergies, although some children outgrow their food allergy as they get older.

A food allergy is a different condition from a food intolerance. A food intolerance does cause discomfort and a range of symptoms. However, a food intolerance does not involve a reaction from the immune system and is usually less harmful.

Symptoms of Food Allergies

The range and extent of food allergy symptoms will vary from person to person. For example, one person’s reaction to a particular food may cause discomfort, but the symptoms may not be severe.

On the other hand, some people may have a life-threatening reaction.

Typically, food allergy symptoms arise within anywhere between a few minutes to a couple of hours after eating the allergen.

Common signs and symptoms of food allergy include:

• Itching or tingle in the mouth and on the tongue
• An itchy skin rash
• Constipation or diarrhea
• Congestion or difficulty breathing
• Nausea or vomiting
• Abdominal pain
• Dizziness or fainting
• Swelling of the throat, tongue, lips, or face.
  

Irritable Bowel Syndrome

Irritable bowel syndrome is a common condition that affects the large intestine. Symptoms include cramping, constipation, diarrhea, gas, and bloating. Recent studies suggest that food allergies may not only play a role in IBS but may even be a causal factor. (Mansueto et al., 2015)

IBS sufferers who also have food allergies usually have diarrhea as their primary symptom. If the food allergy is discoverable, the symptoms of IBS can be eliminated. (Imcleod, 2015)

Anaphylaxis

For people with a severe food allergy, certain foods can trigger a reaction known as anaphylaxis. Typically, anaphylaxis occurs within minutes after a person has eaten the allergen.

Around 20% of people experience a second wave of anaphylaxis within two hours of the first symptoms. (Food Allergy Research and Education, n.d.)

Symptoms of anaphylaxis include:

• Constriction of the airways
• Trouble breathing
• Dizziness and fainting
• Low blood pressure
• Weak pulse
• Loss of consciousness
  

Anaphylaxis can be life-threatening. Anyone who is showing signs or symptoms of this type of reaction should be taken to a hospital immediately.

Causes and Risk Factors

In a healthy person, the immune system detects when pathogens such as viruses or bacteria enter the body, and it attacks them. In some situations, the immune system makes an error and attacks a substance that is not harmful to the body.

If you have a food allergy, when your immune system detects the presence of a particular food in your body, it treats the substance as an enemy.

Your immune system will produce the antibody immunoglobulin E (IgE) to fight the food allergen. IgE antibodies trigger the release of chemicals, such as histamine, which cause an allergic reaction.

Risk factors for food allergies include:

• A family history: You are at a greater risk of a food allergy if a direct family member suffers from a food allergy or a related condition such as asthma, eczema, or hay fever.
• Other related conditions: If you already have one food allergy, you are at a higher risk of developing an allergy to another food. Your risk level increases if you have asthma, eczema, or hay fever.
• Age: Food allergies are more common in young children. Often, children will grow out of their food allergy.
  

Risk factors for anaphylaxis include:

• If you are a teenager or younger
• If you have a history of asthma
• If you delay the use of epinephrine for your allergic response
• If you do not experience symptoms such as hives or other skin issues
  

Most Common Food Allergens

You can be allergic to just about any food, but in the United States, eight specific foods are responsible for the most allergic reactions. These are:

• Cow’s milk
• Tree nuts
• Peanuts
• Eggs
• Fish
• Shellfish
• Wheat
• Soy
  

Certain food additives may also cause an allergic reaction.

Diagnosis

Initially, your doctor will ask you about your general medical history and your history of food allergy symptoms. You must be prepared to provide detailed information about:

• The type of food you believe may have caused the allergic reaction
• The length of time it took for symptoms to occur
• The symptoms you experienced
• How long the symptoms lasted
  

Your doctor may order a blood test or perform a skin-prick test. A blood test is designed to measure the amount of IgE in your bloodstream compared to the particular food tested. This type of test is not as sensitive as a skin scratch test.

A skin test involves the application of allergen extracts to the skin through a small scratch. A small amount of histamine or glycerin will be applied to your skin —  to make sure that your skin reacts normally.

The test causes only minor discomfort and takes between 15-20 minutes. It is usually conducted on your back or forearm. The test is considered positive if a small bump appears at the site of an allergen application.

Your doctor will assess the results of your tests and determine the type of food allergy you have. You will then need to avoid eating that particular food to prevent further symptoms.

A food allergy is an abnormal response to certain foods. In some cases, people may have a severe reaction to a food allergen or one which is life-threatening. If you think you have a food allergy, you should seek medical advice.

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