Food Allergy Types: Complete Guide to Classifications, Symptoms & Testing

Food allergy is an undesirable immune response when your body detects certain foods as a threat and overreacts. Different types of food allergies, including immunoglobulin E allergies, affect various people, leading to different food allergy symptoms. Many people are confused about food intolerances; various food allergy types are different from food intolerances. Different types of food allergy are a negative response from the immune system, while food intolerances are associated with the gut.

So basically, food allergies are a negative reaction of the immune system that causes mild to fatal symptoms. Mainly, there are two types of food allergies called IgE-mediated allergies and non-IgE-mediated allergies, both of which result in allergic symptoms. Some people may have both of these allergies, causing subtle to life-harming reactions, which can escalate into a severe allergic reaction that can even require emergency medical attention.

A food allergy is when your body recognizes certain foods as a threat and reacts abnormally, causing reactions. When the immune system overreacts, it leads to trigger symptoms such as hives, itching, swelling, breathing difficulties, and even life-threatening anaphylaxis. The food allergy reaction usually appears soon after eating the culprit food, even if you eat it in a very small amount.

Food allergies are different from food intolerances. Food allergy is associated with an immune system response that causes severe symptoms and can be fatal. On the other hand, food intolerance is associated with the digestive system and usually only causes gut-related symptoms that are typically not life-threatening.

Talking about food allergy prevalence around the world, around 1-2% of the global population experiences food allergies; however, it may significantly vary by age and region. In India, it's quite low, around 0-14% in children. Common food allergens that cause food allergy, especially in packaged foods, are considered major food allergens, such as peanuts, milk, and gluten.

Various food allergy types can significantly impact the health and daily life of the sufferers. Understanding the exact type of food allergy you are suffering from matters the most because it is associated with how soon symptoms appear, the severity of the symptoms, and how to effectively manage food allergies, especially in those at risk of developing food allergies.

Different allergies are detected through different diagnostic tests. For instance, IgE-mediated allergies are detected through a blood test or skin-prick test, while non-IgE-mediated allergies are usually detected through symptom tracking and elimination. The understanding of food allergy types, including true food allergy, allows accurate diagnosis that helps prevent confusion between food allergy and food intolerance.

A better understanding of various types of food allergies allows efficient symptom management. For instance, life-threatening allergic reactions can be managed by strictly avoiding and being ready with emergency medicine. Some food allergies usually cause issues or digestive concerns that can be managed with conscious diet planning, including careful reading of food labels.

Being aware of different types of food allergies allows early and accurate diagnosis that reduces the potential risk of malnutrition, chronic inflammation, and severe reactions. Knowing the triggers, especially the suspected allergen, helps you prevent possible complications, including a life-threatening reaction.

Knowing about food allergies, eating consciously, and meal planning contribute to effective management and a better quality of life.

So now you must be thinking, actually, how many types of food allergies are there? So let's get into the food allergy classification system and understand various types of food allergies, including non-IgE-mediated food, as highlighted in food allergy research.

Here are the primary classification methods as mentioned below:

• IgE-Mediated Allergies: This type of food allergy is triggered by immunoglobulin IgE antibodies, and the symptoms usually appear after a few minutes to hours of eating the problematic food. For instance, peanut allergy and shellfish allergy.

• Non-IgE-Mediated Allergies (Delayed): These are not associated with IgE antibodies but are the reaction of other parts of the immune system. The symptoms usually appear after some hours to days of eating the problem food. For instance, wheat allergy and milk allergy (in infants).

• Mixed IgE and Non-IgE Allergies: Mixed type allergies involve both IgE and Non-IgE allergies and their reactions. For instance, Eosinophilic esophagitis and some food-protein-associated enterocolitis.

• Immediate Reactions (IgE-Mediated): The reaction is visible after a few minutes to hours of eating the allergen-containing food. The symptoms include itching, swelling, hives, and breathing difficulties. Peanut allergy and milk allergy in kids.

• Delayed Reactions (Non-IgE-Mediated): Typically, the reaction appears after several hours to days of consuming the allergen. The symptoms include skin rashes, digestive problems, and chronic gut inflammation. Wheat and soy allergies and milk protein allergies in infants.

• Mild Food Allergies: The common symptoms include mild rash, itching, and mild stomach-related problems.

• Moderate Food Allergies: The common symptoms include swelling, hives, diarrhea, and vomiting.

• Severe Food Allergies (Life-Threatening): The common symptoms include low blood pressure, breathing difficulties, and anaphylaxis.

The WHO classifies food allergies depending on the type of immune response, as mentioned in the table below, which is crucial for diagnosing food allergy.

As per the clinic diagnosis, food allergies are categorized depending on the diagnosis and management as mentioned below:

When it comes to the most common types of allergic reactions to food, IgE-mediated food allergies are the winners when discussing most food allergies. IgE-mediated food allergies are a result of an improper immune response that usually happens immediately after consuming the trigger food.

The immediate hypersensitivity is caused by histamine release that is triggered by IgE antibodies. The symptoms are visible within a few minutes to hours after consuming the allergen. The symptoms, resulting from an allergic response, are itching, swelling (face, lips, or tongue), hives, abdominal cramps, vomiting, diarrhea, shortness of breath, and, in rare cases, anaphylaxis. Some most common examples are peanut allergy, tree nut allergy, milk allergy, egg allergy, and shellfish allergy.

The allergy syndrome is caused due to the cross-connection between food proteins and pollen proteins; IgE-mediated. The allergy reaction, which may also be part of the pollen food allergy syndrome, is visible immediately after ingesting the problematic foods, such as nuts, fruits, or vegetables. The symptoms include itching and swelling around the mouth, throat, or lips. Some common examples are hazelnut, apple, celery, and carrot.

The IgE-mediated allergic reaction is triggered by the combination of problem food and physical activity. The reaction occurs after a person consumes an allergen before the exercise. The symptoms include swelling, hives, low blood pressure, vomiting, and anaphylaxis (rare and severe). Some common examples are wheat allergy, shellfish allergy, and celery allergy associated with exercise.

IgE-mediated food allergies are caused by certain foods that trigger an immune system response. These foods are called allergens, and the common examples are:

• Peanuts

• Tree Nuts

• Milk

• Eggs

• Shellfish

• Wheat

• Soy

• Sesame

The symptoms of IgE-mediated food allergies are visible immediately after consuming the allergen, typically within a few minutes to hours.

• Skin Reactions: Hives, itching, swelling, eczema flare-ups.

• Respiratory Symptoms: Wheezing, difficulty breathing, stuffy or runny nose, coughing or sneezing, hoarseness.

• Gastrointestinal symptoms: Nausea, vomiting, diarrhea, stomach pain, or cramps.

• Cardiovascular symptoms: Blood pressure fluctuations, dizziness, fainting, or shock.

• Anaphylaxis warning signs: Severe reaction that affects multiple organs, including skin, gastrointestinal, respiratory, and cardiovascular, that may necessitate immediate emergency treatment.

Non-IgE food allergy types or delayed food allergy types are caused by immune responses without involving IgE antibodies. The symptoms are usually visible after a few hours to days after consuming the problematic food.

• T-cell-mediated reactions

• Delayed onset of symptoms (A few hours to days)

• Standard tests may not be able to diagnose these food allergies

• Non-IgE food allergies are more common in kids and infants

Food Protein-Induced Enterocolitis Syndrome: The symptoms typically appear 2-6 hours after consuming the allergen. The common symptoms include consistent diarrhea, vomiting, dehydration, lethargy, and low blood pressure (severe). Typically, the triggers include milk, soy, oats, and rice.

Food Protein-Induced Allergic Protocolitis: The symptoms usually appear after a few days of ingesting the allergen. The common symptoms include mild diarrhea, blood-streaked stools, and mucus in the stool. Typically, the sufferers are infants, and the common triggers include soy and cow’s milk.

Food Protein-Induced Enteropathy: Typical chronic reaction over days to weeks. The common symptoms include vomiting, chronic diarrhea, gradual growth, and poor nutrient absorption. Typically, the sufferers are infants and kids, and the common triggers include wheat, milk, and soy.

Usually, people experience symptoms after hours to days that are gradual, subtle, and mainly impact the digestive system.

• Chronic digestive issues: vomiting, delayed or chronic diarrhea, abdominal pain, mucus or blood in stool, slow growth, and poor nutrient absorption.

• Skin manifestations: Persistent rashes and eczema flare-ups.

• Other signs and symptoms: Picky eating or food refusal in children and irritability or lethargy.

Here are the nine most common types of food allergies recognized by the FDA and WAO that you should be aware of.

Milk Allergy: Milk allergy is the most common food allergy in infants and young children. It may outgrow by the age. The symptoms include eczema, diarrhea, vomiting, hives, and severe anaphylaxis.

Peanut Allergy: Usually, the peanut allergy is considered a lifelong allergy. Peanut allergy is associated with severe reactions such as anaphylaxis, even if the allergen is ingested in a very small amount.

Tree Nut Allergies: These types of food allergies are considered lifelong allergies with the risk of severe reactions. The most common examples are cashews, almonds, walnuts, and pistachios.

Shellfish Allergy: Usually, the shellfish allergy involves adult onset and can extend lifelong. Typically, this type of food allergy is caused by prawns, lobster, crab, and shrimp. It may trigger anaphylaxis.

Fish Allergy: This type of allergy involves adult-onset and usually lasts lifelong. It may trigger life-threatening IgE-mediated reactions.

Egg Allergy: This type of allergy is common in kids. Usually, egg whites are considered more allergenic than compared to the yolk. The symptoms include digestive problems, skin reactions, and, in severe cases, respiratory problems.

Wheat Allergy: This type of allergy can cause IgE-mediated allergy or celiac disease and may contribute to exercise-induced responses in vulnerable people.

Soy Allergy: Soy allergy is more common in kids and infants and may outgrow with age. Hidden exposure to soy is possible, as it is usually present in most processed foods.

Sesame Allergy: Sesame is the newest major allergen that is being recognized more commonly. It may involve severe reactions, and the common symptoms include swelling, hives, respiratory problems, and digestive symptoms.

In India, food allergies may vary due to regional variations, such as exposure to certain foods and various types of diets and cuisines. Understanding the local dietary staples can help recognize and manage various food allergy types in India, especially to avoid accidental exposure.

Common allergens include wheat, milk, eggs, nuts, and mustard. The typical reactions, especially in those with multiple food allergies, are digestive problems, skin rashes, and mild to moderate IgE-mediated reactions. Wheat allergies and gluten allergies are most common in North India.

Common Allergens in South India include seafood, coconut, peanut, sesame, and rice. The typical reactions include subtle to severe IgE-mediated allergic reactions.

Common allergens in East India include nuts, eggs, mustard seeds, and fish. The typical reactions include digestive concerns, skin reactions, and respiratory issues, and may sometimes be confused with food poisoning. Seafood allergies are most common in East India.

In the West region, the commonly recognized allergens are seafood, wheat, milk, peanuts, and tree nuts. Typical reactions, as noted in food allergen labeling, include mild to fatal IgE-mediated allergic reactions and anaphylaxis.

Confused about mild vs severe food allergy types? Let’s explore the different types of food allergies based on severity.

• Common examples are peanuts, eggs, and milk

• Symptoms include mild itching, stomach issues, and hives or rashes

• Avoid the problem food and carry antihistamines( OTC medication) for emergencies

• Involves multiple systems

• Common symptoms include diarrhea, vomiting, swelling, hives, and mild respiratory problems.

• Some common examples are soy, shellfish, and tree nuts.

• Completely avoid the allergen and take antihistamines if required.

• Involves life-threatening symptoms

• Major risk of anaphylaxis

• Common symptoms include wheezing, breathing difficulty, blood pressure drop, fainting, and affect various organs.

• The most common examples include tree nut, peanut, and shellfish allergies.

• These can be easily managed through emergency care and using EpiPen.

• These food allergy types can be life-threatening.

These are the allergic reactions that run in families from generation to generation. It doesn’t mean that if someone had a certain food reaction in your family history, you will also suffer from the same. For instance, seafood allergies, milk allergies, egg allergies, peanut allergies, and tree nut allergies are examples of allergic diseases.

This type of food allergy is caused by certain triggers at certain seasons or times of the year, usually associated with pollen allergies. For instance, hazelnut, almond, carrot, celery, kiwi, cherry, pear, and apple.

These types of food allergies are caused by consuming certain foods before exercise that induce an allergic reaction. Common triggers include nuts, celery, shellfish, wheat, and sometimes other foods such as fruits.

• Different food allergies may appear differently at certain ages, as mentioned below:

• Infants and Young kids (milk, wheat, eggs, peanuts, and soy)

• Children and Teenagers (peanuts, tree nuts, shellfish, and fish)

• Adults (peanuts, tree nuts, fish, shellfish, certain fruits and vegetables)

Let's understand different types of allergies in food based on different types of food reactions:

• Symptoms appear after a few minutes or hours of eating the problem food.

• Involves an IgE-mediated mechanism triggered by the release of histamine.

• Common examples include milk, egg, peanut, and shellfish.

• Symptoms appear after 6-72 hours of allergen exposure.

• Involves T-cell-mediated responses and other immune pathways.

• Common examples include eosinophilic gastrointestinal disorders.

• These allergies are a combination of immediate and delayed responses.

• Involves IgE and non-IgE-mediated immune responses.

• Common examples include wheat allergies and eosinophilic esophagitis.

Swelling, hives, redness, itching, and eczema flares

Coughing, throat tightness, nasal congestion, wheezing, and breathing difficulty

Abdominal pain and cramping, nausea and vomiting, diarrhea

Involves multi-organ loss of consciousness, blood pressure fluctuations, and anaphylaxis

Various food allergy testing procedures can help recognize the trigger foods, allowing better management and efficient treatment.

• Skin Prick Tests

• Blood Tests (Serum IgE)

• Diet Elimination

• Oral and Supervised Food Challenges

• Ptach Testing for Delayed Reactions

• Endoscopic Evaluations

• Component-Resolved Diagnostics

• Basophil Activation Tests

You can manage different food allergy types depending on the type of allergy, associated symptoms, and severity of the reaction. The goal of these strategies is to treat symptoms and prevent reactions, especially when symptoms occur.

• Avoidance Strategies

• Treatment by Allergy Type

Mainly, there are nine types of food allergies caused by various allergens, including milk, peanuts, tree nuts, eggs, wheat, fish, soy, sesame, and shellfish. Typically, Food allergies are classified as IgE-mediated, non-IgE-mediated, and mixed reactions. Proper diagnosis of food allergy is crucial to avoid unnecessary dietary limitations and to avoid severe reactions. Accurate diagnosis can help prevent the risk of life-threatening anaphylaxis, enabling efficient management. Improper diagnosis can contribute to poor life quality, nutritional deficiencies, and lack of emergency awareness. In case of severe reactions, seek medical help and visit your healthcare provider.