Allergy Diet Guide: What You Need to Know

Common Food Allergies

Almost any food can cause an allergic reaction. Some foods, however, are more likely to cause food allergies than others. These foods include eggs, cow's milk, shellfish, fish, soy, and wheat. Other allergens include peanuts and tree nuts such as walnuts, almonds, and pecans. In the United States, these foods cause 90% of allergic reactions. People are less likely to have a strong allergy to fruits and vegetables.

Symptoms

A person who is having an allergic reaction to food will often experience symptoms within a two-hour period. Sometimes, however, they may not start experiencing symptoms until as long as six hours later. Because food allergies affect all parts of the body, symptoms may manifest in various places. Symptoms that involve the gut may include stomach cramps, severe diarrhea, and vomiting. Respiratory symptoms may include wheezing, difficulty breathing, shortness of breath, or a frequent and repetitive cough. Common symptoms that involve the mouth and throat include a swollen tongue, tight throat, itchy mouth, and trouble swallowing.

Other food allergy symptoms include pale skin, earlobes or lips turning blue, dizziness, a weak pulse, and feeling faint. Itchy skin, including the palms of the hands or the soles of the feet, may also occur. In severe cases, a person may have a dangerous reaction known as anaphylaxis. With anaphylaxis, a person can go into shock within minutes as their airways suddenly narrow and their blood pressure begins to quickly drop. Some common symptoms of anaphylaxis include swelling of the tongue, lips, or eyes, itching, vomiting, slurred speech, and a rapid pulse. If a person's food allergy triggers anaphylaxis, they must immediately receive a shot of epinephrine, and 911 should be called.

Food Allergy vs. Intolerance

Food allergies and food intolerance are two often confused conditions. They both trigger physical responses to food, but there are certain differences in how the condition affects the body and the severity of the symptoms. Food intolerance affects only the digestive system, which cannot break down certain nutrients that are in a specific food. The symptoms of food intolerance are unpleasant but not life-threatening. Food allergies, however, are an immune system response to a certain nutrient in a specific food. The symptoms of food allergies are more severe than those associated with food intolerance and can be fatal.

When to Seek Emergency Help

Knowing when to contact emergency services during an allergic reaction to food can be the difference between life and death. Immediately seek emergency help anytime a person shows signs of a severe allergic response, such as rapid swelling of the tongue or throat, to food that they've eaten. This is crucial even if they've received epinephrine and the symptoms have resolved. When calling 911 for someone after giving them a shot of epinephrine, it's important to inform responders of that fact.

People who are having multiple types of symptoms should also seek emergency help. An example would be a person who experiences stomach cramps, dizziness, and hives. Shock is another major concern; if a person shows signs of shock, call 911. Signs of shock include thirst, heavy sweating, cool skin, a feeling of impending doom or confusion, and feeling faint or lightheaded.

Diagnosis and Treatment

To diagnose food allergies, doctors start with questions about one's history of symptoms, what foods cause problems, and any food allergies in the family. A physical examination is typically the next step; this exam will also look for other problems that could be causing the symptoms.

Testing also plays an important role in diagnosing food allergies. This includes a skin test, a blood test, and an elimination diet. The skin test involves placing a tiny amount of the food that is suspected to be an allergen on the skin and then pricking the skin to allow some of it beneath the surface. If there is a reaction, such as a rash or a bump, the food is likely an allergen. A doctor may also perform a blood test. With a blood test, drawn blood is sent to a laboratory for testing against various foods for high amounts of immunoglobulin E (IgE), which would show that there is an allergic reaction.

An elimination diet is a simple and non-invasive test for suspected food allergies. It involves taking certain foods out of one's diet for several weeks. These foods are then added back to the diet, one at a time. If a reaction occurs, the food that triggered the response may be an allergen. This test could also point to food intolerance, so it's not 100% accurate in diagnosing food allergies without further testing.

The best way to treat food allergies is to avoid foods that cause an allergic response. However, this is not completely foolproof because of the risk of accidental exposure. Antihistamines, prescribed or over the counter, are a way to treat mild reactions, such as itching. For severe, life-threatening reactions, an injection of epinephrine may be necessary. People prone to severe reactions should carry an epinephrine auto-injector at all times to protect themselves in the event of accidental exposure.

There are several forms of experimental treatments that are meant to help desensitize people to the foods that they're allergic to. Two of these are oral immunotherapy (OIT) and epicutaneous immunotherapy (EPIT). At an appointment for OIT, a doctor gives the patient a small amount of the food that they are allergic to, either by placing it under the tongue or having the patient swallow it. The amount given is gradually increased over time to potentially build up their tolerance to it. When a person undergoes EPIT, the doctor administers a small amount of protein from the food allergen through a skin patch. As with OIT, the amount of exposure to the protein is increased gradually over time to encourage tolerance of it.

Avoiding Peanuts

Peanut allergies are one of the most dangerous food allergies, and it is crucial that sufferers do not come into contact with them. But this can be more difficult than one might initially think. The first and most obvious thing to do is to not eat peanuts or anything that may contain peanuts. Unfortunately, cross-contamination or even physical contact may trigger an allergic reaction. One way to avoid coming into contact with potentially contaminated food is to always check food labels. The labels will list ingredients and include warnings such as "contains peanuts," "produced on shared equipment with peanuts," or "made in a facility with peanuts."

Knowing what foods sometimes contain peanuts is also important. Chili, crumb toppings, certain ethnic foods, flavorings, hydrolyzed plant protein, marzipan, and mole sauce are some of the foods that may potentially have peanuts in them. One should also avoid fried foods, such as French fries, which may be fried in oil that contains peanuts. When eating out, avoid eating at buffets where traces of peanuts from one dish may transfer to multiple dishes via serving utensils. When eating at restaurants, one should let the server know that they or their child have a peanut allergy. Ask about ingredients and for foods to be prepared on surfaces that have not been in contact with peanut-containing ingredients.

• Food Allergy Essentials: Common Allergens
• Common Food Allergies
• Food Allergies: What You Need to Know
• Food Allergies Around the Globe
• Allergic Conditions: Food Allergy
• Food Allergy Symptoms and Causes
• Preventing a Nut Allergy Reaction
• Food Allergy vs. Intolerance: What's the Difference?
• What's the Difference Between a Food Allergy and a Food Intolerance?
• Surprising Sources of Peanuts
• Food Allergies: When to Call
• Anaphylaxis
• Peanut Allergy
• Food Allergen Graph: Avoiding Peanuts, Tree Nuts, Egg, Corn, and Wheat Ingredients
• Food Allergies Diagnosis and Treatment
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• Peanuts: Lifestyle and Home Remedies
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