A food allergy is an adverse immune response to specific proteins in certain foods. When someone with a food allergy consumes an allergen, their body’s immune system reacts by releasing chemicals that can lead to various symptoms, ranging from mild to severe. Food allergies are relatively common and affect millions of people globally.¹

In contrast, food intolerance is a non-immune response that arises from the body's inability to digest certain substances properly. Unlike allergies, intolerances typically involve gradual and less acute symptoms, such as digestive system issues. The mechanisms behind food intolerances often include enzyme deficiencies or pharmacological reactions.²

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11 Common Symptoms of Food Allergies

Food allergies can manifest in various ways, and the severity of symptoms can range from mild to severe. It's essential to be aware of the signs that someone might be allergic to certain foods. Here are 11 common symptoms of a food allergy.

• Itching or Tingling in the Mouth<p style="margin: 0;">Mouth symptoms, such as itching or tingling, may be present during a food allergic reaction<p>

• Dizziness<p style="margin: 0;">A drop in blood pressure during a severe allergic reaction can lead to dizziness or lightheadedness<p>

• Hives<p style="margin: 0;">The development of red, itchy welts on the skin, known as hives, is a common allergic reaction<p>

• Swelling in the Face<p style="margin: 0;">Allergic reactions can lead to swelling, especially around the face, lips, and tongue. This can be particularly concerning if it affects the airways<p>

• Vomiting<p style="margin: 0;">Digestive symptoms such as nausea and vomiting can be signs of a food allergy, especially in the case of severe reactions<p>

• Shortness of Breath or Coughing<p style="margin: 0;">Shortness of breath, coughing, or having trouble breathing may indicate a severe allergic reaction<p>

• Anaphylaxis<p style="margin: 0;">This is a severe, life-threatening allergic reaction. Symptoms of anaphylaxis include difficulty breathing, a drop in blood pressure, and loss of consciousness. Anaphylaxis requires immediate emergency medical attention<p>

• Abdominal Pain<p style="margin: 0;">Some individuals may experience stomach cramps or pain due to a food allergy<p>

• Runny or Stuffy Nose<p style="margin: 0;">Allergic reactions to certain foods can mimic hay fever symptoms, including sneezing or having a runny or stuffy nose<p>

• Diarrhea<p style="margin: 0;">Allergic reactions can affect the gastrointestinal system, leading to diarrhea<>p

• Anxiety or Confusion<p style="margin: 0;">In some cases, individuals may experience feelings of anxiety or confusion during an allergic reaction³<p>

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What Causes Food Allergies?

Food allergies are triggered when the immune system mistakenly identifies proteins in certain types of food as harmful invaders, such as viruses or bacteria. In individuals with food allergies, the immune system overreacts to these specific proteins, known as allergens, by producing antibodies called immunoglobulin E (IgE). Upon subsequent exposure to the same allergen, the IgE antibodies signal immune cells to release various chemicals, such as histamines, leading to the manifestation of allergic symptoms.⁴ Individuals have a slightly higher chance of having a food allergy if they or a close relative have existing food allergies, asthma, or eczema.

Age also plays a crucial role in the manifestation and development of food allergies. Infants and young children are more susceptible to food allergies, and some allergies may emerge early in life. Common allergens in early childhood include milk, eggs, and peanuts. Notably, certain food allergies may be outgrown as children age, particularly those to dairy products, eggs, wheat, and soy. On the other hand, allergies to peanuts, tree nuts, fish, and shellfish are more likely to persist into adulthood.⁴

Below are a few of the most common food allergies.

Egg

Allergic reactions to eggs typically involve the proteins found in the egg whites. Symptoms may include skin reactions, gastrointestinal distress, and respiratory issues.

Milk

Milk and its byproducts are a common allergen, especially in infants and young children. Allergic reactions to milk can range from mild to severe and may involve symptoms such as hives, digestive issues, and, in severe cases, anaphylaxis.

Soy

Soybeans and soy-based products are common allergens. Allergic reactions to soy can manifest as skin reactions, digestive issues, and respiratory symptoms.

Wheat

Wheat allergies can lead to various symptoms, including skin rashes, digestive problems, and respiratory issues. It's important to note that wheat allergy is distinct from non-celiac gluten sensitivity and celiac disease.

Peanuts

Peanut allergies are known for their severity and potential for anaphylaxis. Even small amounts of peanuts or peanut products can trigger allergic reactions, making it crucial for individuals with this allergy to avoid all forms of peanuts.

Tree Nuts

This category includes nuts such as almonds, pecans, walnuts, cashews, pistachios, and others. Allergies to tree nuts can cause a range of symptoms, from mild skin reactions to severe anaphylaxis.

Shellfish

This category includes crustaceans like shrimp, crab, lobster, and mollusks like clams, mussels, and oysters. Shellfish allergies can be particularly common and may cause severe reactions.

Fish

Allergic reactions to fish, including both freshwater and saltwater varieties, can be severe. Symptoms may include skin reactions, gastrointestinal issues, and respiratory distress.

Sesame

Sesame allergies are becoming increasingly recognized as a significant allergen. Allergic reactions to sesame can include skin symptoms, digestive issues, and respiratory problems.³

Some Fruits or Vegetables (Pollen-Food Allergy Syndrome)

Pollen-food allergy syndrome (PFAS), also known as oral allergy syndrome, is a condition where certain proteins in raw fruits, vegetables, and nuts trigger allergic reactions in individuals who are already allergic to pollen. This phenomenon occurs due to cross-reactivity between proteins in certain foods and airborne pollen allergens.⁵ 

Food Allergy Treatment and Diagnosis

To test for most food allergies, a doctor will perform a skin prick test to test for most food allergies. In this test, small amounts of allergen extracts are applied to the skin, usually on the forearm or back. The skin is then pricked to introduce the allergen. A flare reaction indicates a positive response to the allergy test. 

Alternatively, a doctor may perform a RAST blood test, where blood is drawn to measure the level of specific IgE antibodies produced in response to allergens. Elevated IgE levels indicate sensitivities to certain allergens.⁶

The most effective way to manage food allergies is to avoid the allergenic foods entirely. Reading ingredient labels, informing restaurants about allergies, and being cautious about cross-contamination is crucial to implementing this strategy. Epinephrine autoinjectors are used in severe allergic reactions to rapidly reverse symptoms. Also known as EpiPens, these must be carried with you at all times to use during emergencies. In terms of medications, antihistamines and corticosteroids can help manage mild to moderate allergic reactions.⁶

It's crucial for individuals with food allergies to work closely with allergists to determine the most appropriate testing methods and treatment plans tailored to their specific allergies and health conditions. Regular follow-ups and communication with healthcare providers are essential for effective management. Working with a registered dietitian to brainstorm food choices and alternatives may also be helpful for those not accustomed to navigating food allergies. 

Prevention

When diagnosed with a food allergy, implementing preventive measures is crucial to minimize the risk of accidental exposure and ensure overall well-being. Here are some key prevention recommendations.

Read Food Labels Diligently

Carefully read ingredient labels on all packaged foods to identify potential food allergens. Be aware of alternative names for allergens and educate yourself about common sources of hidden allergens, including food additives.

Be Cautious About Cross-Contamination

Inform those handling your food about your allergy, and request separate utensils and preparation surfaces. Be cautious when using shared kitchen equipment and facilities.

Carry Medications

Keep your medications with you at all times, and make sure family members, friends, and coworkers are aware of their location and how to use them in case of an emergency.

Plan Ahead for Social Gatherings

Communicate your food allergies in advance, bring safe food options, or eat before attending events where the menu may pose a risk.

Create an Emergency Action Plan

Work with your healthcare provider to create an emergency action plan that outlines the steps to take in case of accidental exposure. Share this plan with family members, close friends, and coworkers.

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