Food allergies: Causes, symptoms and treatment

Have you ever felt navigating a meal with food allergies is like tiptoeing through a culinary minefield? You’re not alone. Millions are wrestling with this reality every single day. 

Today, we’re stepping into this world together, exploring the what, why, and how of food allergies – their causes, different types, symptoms, and even the ways to manage them. 

Whether you’re personally touched by this or looking out for someone who is, this guide is for you. We’ll dive into everything from the role of genes and environment to the breakthroughs in medication. 

This is more than just an overview; it’s a key to understanding, managing, and potentially overcoming food allergies. Join us on this journey to demystify this prevalent health concern.

What are food allergies?

The immune system, which protects the body from harm, is responsible for causing food allergies. Sometimes, the immune system mistakenly identifies a protein or other component of food as a threat, leading to an allergic reaction.

In trying to defend the body, the immune system produces substances like Immunoglobulin E (IgE) antibodies, leading to various symptoms of an allergic reaction.

But here’s a twist: only some with these antibodies experience symptoms. It’s like having a security system installed, but it never actually goes off, even if there’s an intruder. 

That’s why an allergic reaction to food isn’t just about what happens in our bodies on a molecular level but also how we feel and experience it.

These experiences, or symptoms, can range from mild (think itching, rashes, or stomach upset) to severe (like difficulty breathing or loss of consciousness). 

In severe instances, food allergies can lead to a dangerous reaction called anaphylaxis, which can be life-threatening. It’s like the red alert of allergic responses and requires immediate medical attention.

These allergies can pop up at any age but are especially common in children. The symptoms can change over time; while some outgrow their food allergies, others have them for life. 

So, when we talk about food allergies, we’re not talking about just disliking a particular food or getting a bit gassy after eating beans. 

It’s about the immune system’s overzealous reaction to harmless proteins in our food, causing uncomfortable and sometimes serious symptoms. 

By understanding this, we can better manage food allergies and ensure they don’t manage us.

Are food allergies common?

The answer is a resounding yes. These tricky little inconveniences are more prevalent than you might think, affecting people all over the globe.

According to the Centers for Disease Control and Prevention, an estimated 8% of children are affected by food allergies in the US [1].

That’s almost 10% of the population! And it’s not just adults. Around 5.6 million children under the age of 18 suffer from food allergies. That’s about one in 13 children, or in classroom terms, roughly two kids in every classroom.

But it’s not just an American issue. Food allergies have a global footprint, affecting millions in Europe, Asia, Africa, and elsewhere. 

Whether it’s peanut allergies in the United States, seafood allergies in Japan, or celery allergies in Switzerland, food allergies have spread their tentacles far and wide.

Food allergies also show no preference for gender, affecting both men and women. However, research does suggest that boys are more likely to develop food allergies during childhood than girls. 

As for adults, women are more prone to developing food allergies.

In short, food allergies are widespread, affecting people of all ages, genders, and regions. 

Types of food allergies

Food allergies are as diverse as our food. Different people can have allergies to different types of food and the level of their reaction may also differ.

Here are eight of the most prevalent types of food allergies [2].


One of the most common and severe food allergies is peanut allergy. This happens when your immune system wrongly identifies proteins in peanuts as harmful intruders [3].

In response, your body initiates an allergic reaction that can cause symptoms ranging from mild to severe. Common symptoms include skin reactions like hives or redness, digestive problems, runny nose, and shortness of breath. 

In severe cases, individuals may experience anaphylaxis, a potentially fatal allergic reaction that requires immediate medical attention.

Peanuts are legumes, which means they belong to the same family as beans and lentils. But a peanut allergy isn’t the same as a tree nut allergy. While some people might be allergic to both, many are allergic to one or the other.

Peanut allergies tend to be lifelong, although about 20% of children with peanut allergies outgrow them. They’re also among the most common causes of food-related anaphylaxis, with even trace amounts capable of triggering a reaction. This is why it’s crucial for individuals with a peanut allergy to altogether avoid peanuts and peanut-derived products.

Living with a peanut allergy requires careful management, including reading food labels thoroughly, carrying epinephrine auto-injectors for emergencies, and informing others about the allergy to ensure safety. 


Milk and dairy

While often mistaken for lactose intolerance, a milk allergy is an adverse immune response to the protein in milk. But unlike lactose intolerance, a milk allergy can cause a serious or life-threatening reaction.

Milk and dairy allergy is an adverse immune response to proteins, casein and whey. The resulting allergic reaction can range from mild symptoms like hives, stomach upset, or nasal congestion to severe ones like anaphylaxis [4].

This allergy is most common in infancy and early childhood, although it can develop at any age. While many children outgrow it, some continue to experience symptoms into adulthood. 

Managing a milk and dairy allergy involves completely avoiding milk and dairy products, carefully examining food labels, and using alternative calcium and vitamin D sources. 


Egg allergy is another common food allergy, especially in children. Reactions can occur to either the egg white or the egg yolk, but are usually associated with the egg white [5]. However, some people can also react to yolk, and it’s often recommended that people with an egg allergy avoid eggs altogether.

Although egg allergies are more common among children, they can still happen at any age and may develop later in life. Fortunately, many children eventually outgrow this allergy as they grow older.

Symptoms can be mild, like a skin rash or a runny nose, or more severe, like anaphylaxis.

Managing an egg allergy involves avoiding foods containing eggs, which can be challenging since eggs are present in many processed foods and are often used in cooking and baking.

Tree nuts

A tree nut allergy is an immune response to the proteins found in tree nuts. This includes nuts like almonds, walnuts, pistachios, cashews, and pine nuts. 

The immune system in someone with this allergy sees these proteins as threats, leading to an allergic reaction. This can cause symptoms like skin rashes, itching, digestive upset, difficulty breathing, or, in severe cases, anaphylaxis.

It’s important to note that peanuts are not tree nuts; they are legumes [6]. However, some people are allergic to both tree nuts and peanuts. 

Additionally, being allergic to one type of tree nut doesn’t necessarily mean you’re allergic to all others. Still, because of the risk of cross-contamination and the severity of potential reactions, many health professionals recommend avoiding all tree nuts if you’re allergic to one type.

Unlike some food allergies, tree nut allergies are usually lifelong. Only about 9% of children with a tree nut allergy outgrow it. Furthermore, tree nut allergies can be serious and are one of the leading causes of fatal and near-fatal allergic reactions to food.

Management of a tree nut allergy involves strict avoidance of the allergen, carrying an epinephrine auto-injector for emergencies, and regular check-ups with a healthcare provider. 


This includes allergies to fish and shellfish. This category includes salmon, tuna, cod, and shellfish, like shrimp, crab, and lobster. 

Some people may also react to mollusks like clams, oysters, and mussels. Interestingly, an individual may be allergic to one type of seafood and not others. 

However, due to the high risk of cross-contact, avoiding all seafood is often recommended if you’re allergic to one type.

Seafood allergies can cause skin reactions like hives or itchiness, gastrointestinal symptoms, wheezing, or anaphylaxis, a severe, potentially life-threatening reaction.

Unlike many other food allergies, seafood allergies tend to first appear in adulthood, with most people experiencing their first allergic reaction as adults [7]. 

They are usually lifelong, with more than 60% of people with a seafood allergy experiencing their first allergic reaction as adults.


Wheat allergy is an immune response to the hundreds of proteins in wheat. It’s not the same as celiac disease, an autoimmune disease triggered by gluten, a specific type of protein found in wheat, barley, and rye. 

It’s crucial to distinguish between wheat allergy, celiac disease, and non-celiac gluten sensitivity. While all three involve reactions to wheat, they are different conditions. 

A wheat allergy involves an immune response to wheat proteins and can cause an immediate allergic reaction. Celiac disease, an autoimmune disorder, results from an adverse reaction to gluten, a specific protein in wheat [8]. 

Non-celiac gluten sensitivity involves symptoms similar to celiac disease but without the same level of intestinal damage.

Symptoms of this allergic reaction can include skin rashes, nasal congestion, digestive issues, difficulty breathing, and in severe cases, anaphylaxis.

Wheat allergies are more common in children, but adults can have them, too. Many children outgrow their wheat allergy, but some continue to have symptoms into adulthood.


Soy allergy is more common in infants and children under three. The good news is that most children outgrow their soy allergy by age 10. 

Symptoms might include hives or other skin reactions, digestive troubles, nasal congestion, or a more severe reaction like anaphylaxis [9].

Managing a soy allergy can be tricky because soy is present in many processed foods, including baked goods, canned tuna, meat products with fillers, and chocolate. Therefore, strict label reading is essential. 

Fortunately, the FDA requires labeling for soy, which makes avoiding it a bit easier. In cases of severe soy allergies, carrying an epinephrine auto-injector and having an emergency plan is crucial.


When someone with a sesame allergy consumes sesame in any form—seeds, oil, or paste—their immune system misidentifies the sesame proteins as harmful. This leads to an allergic reaction, which can include symptoms like hives, itching, digestive problems, breathing difficulties, or in more serious cases, anaphylaxis [10].

Despite its growing prevalence, sesame allergy is often overlooked compared to other food allergies. However, it can be just as severe and life-threatening. 

Sesame allergy is more common in children, but adults can develop it too, and it can persist into adulthood.

These food allergies can manifest in unique ways, impacting individuals differently. The key to managing them lies in proper diagnosis, understanding the allergen, and knowing how to respond during an allergic reaction.

What causes food allergies? 

A food allergy occurs when the body’s immune system mistakenly identifies a protein in food as a harmful invader, like a virus or bacteria. This triggers an immune response, leading to various symptoms of an allergic reaction. 

But what leads the immune system to make this error? Let’s dive into the two main contributing factors: genetic and environmental.


It seems our genes have a say in nearly every aspect of our lives, and food allergies are no different. If your parents or siblings have food allergies, you’re also at a higher risk of developing them. 

This is because food allergies, like many other types, tend to run in families, indicating a genetic predisposition. However, it’s not a certainty; just because your family has food allergies doesn’t mean you will too. It simply increases your chances.


The environment we grow up in and our lifestyle can also play a significant role in developing food allergies. Some research suggests that early exposure to certain allergenic foods may reduce the risk of developing an allergy to that food. 

This concept, known as the “hygiene hypothesis,” posits that living in too clean an environment may increase the risk of allergies by limiting early exposure to germs, which could affect immune system development.

Moreover, factors like a diet lacking in certain nutrients, lack of vitamin D, obesity, and increased use of antibiotics and antacids can alter our gut microbiota, the collection of microorganisms living in our intestines. 

This alteration can affect the balance between the immune system and the microbiota, potentially leading to food allergies.

However, it’s important to note that the exact causes of food allergies are complex and not fully understood. What we do know is that both genetic and environmental factors play crucial roles. 

Symptoms of food allergies

Taking a bite of your favorite meal only to feel strange sensations afterward can be quite disconcerting. This could be a sign of a food allergy. 

Food allergies can trigger symptoms ranging from mild discomfort to severe life-threatening reactions. But what exactly do these symptoms look like?

Mild symptoms

In some instances, the symptoms of a food allergy can be relatively mild, though still uncomfortable. They usually occur a few minutes to a few hours after eating the offending food. These can include:

  • Hives (red spots that resemble mosquito bites)
  • Itching or tingling in or around the mouth
  • Digestive problems, like abdominal pain or diarrhea
  • Nasal congestion or a runny nose
  • Dry, itchy skin rash

While these symptoms can usually be managed with over-the-counter or prescribed antihistamines, monitoring them closely is essential. 

Mild symptoms can rapidly escalate to more severe symptoms, so it’s critical to be prepared.

Severe symptoms

Sometimes, a food allergy can cause more severe and potentially life-threatening symptoms, a reaction known as anaphylaxis. If you experience any of these symptoms, seek immediate medical attention:

  • Difficulty breathing due to the swelling of the throat or a sudden drop in blood pressure
  • Rapid, weak pulse
  • Dizziness, lightheadedness, or fainting
  • Chest pain or tightness
  • Severe and rapid onset of hives or rash

While these symptoms are severe, anaphylaxis is a treatable condition. With immediate treatment, usually with an injection of epinephrine and follow-up care, individuals can recover completely. However, without immediate treatment, anaphylaxis can be fatal.

How are food allergies diagnosed?

Accurately diagnosing a food allergy is a critical step toward managing it, but it’s not as simple as it might seem. It requires careful examination and various tests under the guidance of an allergist or immunologist.

Diagnosis typically starts with a detailed medical history. Your doctor will want to know the specific symptoms you experienced when they occurred and how long they lasted. 

It’s also important to note whether the reaction happened immediately after eating a particular food or later and whether it happens every time you eat it. Your doctor will also consider any family history of allergies.

Next, your doctor might recommend one or more of the following tests:

Skin prick test

This test involves placing a small amount of the suspected food allergen on your skin, usually the forearm, and then lightly pricking or scratching the skin with a needle. If you’re allergic, you’ll likely develop a raised bump (hive) at the test site.

skin prick test
Photograph: microgen/Envato

Blood test

Blood tests can measure the specific antibodies (like immunoglobulin E or IgE) that your body might produce in response to certain foods. A higher amount of these antibodies could suggest a food allergy.

Oral food challenge

This is considered the most accurate test for food allergies. Under strict medical supervision, you’ll eat or drink small amounts of the suspected allergen in increasing amounts over some time, and the doctor will observe for any reaction. A medical professional must perform this test due to the risk of severe reactions.

Elimination diet

This involves removing the suspected food allergen from your diet for a period (usually 2-4 weeks) and seeing if symptoms resolve. Then, the food is reintroduced under controlled conditions to observe for any reaction.

These tests can help establish whether a food allergy exists, but each has limitations and may not always provide clear answers.

In addition, food allergy home test kits are available in the market that provide accurate results. However, working with an experienced allergist or immunologist is essential when seeking a food allergy diagnosis. 

What is the best treatment for food allergy?

Discovering that you have a food allergy can be overwhelming, but it’s important to remember that effective treatment options are available. 

While there’s no cure for food allergies, they can be managed effectively with a combination of avoidance, medication, and emerging treatments. 

Avoidance and management

The most effective way to manage food allergies is to avoid the allergen. This means eliminating the problematic food from your diet completely. 

It can be a challenge, especially considering the prevalence of common allergens in many processed foods, but it’s entirely possible with careful planning.

Avoidance also involves reading food labels carefully, understanding food manufacturing processes, and communicating your dietary needs when eating out or at social events. 

In addition, carrying out an emergency care plan can be vital. This plan should outline what to do in the event of accidental exposure to the allergen, and it can be essential for children attending school or adults in the workplace.


While avoidance is the primary strategy, medications can help manage symptoms after accidental exposure or alleviate mild symptoms. 

Antihistamines can alleviate minor symptoms like hives or itching, while corticosteroids may be used for more severe skin reactions.

However, immediate treatment with an epinephrine auto-injector (an EpiPen) is necessary for severe reactions such as anaphylaxis. 

Epinephrine reduces throat swelling, opens the airways, and maintains heart function and blood pressure. After using an auto-injector, seeking immediate medical attention is still crucial.

Emerging treatments

In recent years, treatments like oral immunotherapy (OIT) have shown promise. OIT involves giving the person with a food allergy small, gradually increasing doses of the allergen to desensitize their immune system [11]. 

However, this method risks severe allergic reactions and is unsuitable for everyone. Researchers continue to investigate new treatment strategies that could lead to a cure.

Closing thoughts

Navigating life with food allergies may seem daunting, but it’s entirely achievable with understanding, careful management, and the right treatment strategies. 

Remember, avoiding allergens, utilizing medications when needed, and staying informed about emerging treatments are key steps toward managing this condition effectively. 

While food allergies may pose dietary restrictions, they offer culinary creativity and resourcefulness opportunities. 

As we look to the future, ongoing research gives us hope for even better treatment options and potential cures. 

So don’t let food allergies limit your zest for life and exploration. Stay vigilant, stay informed, and continue to relish the joy of food in ways that best suit your health needs.


Can food allergies be cured?

There is no definitive cure for food allergies. However, some treatments, like oral immunotherapy, aim to desensitize the body to specific food allergens and have shown promise. However, these are still under active research and are unsuitable for everyone.

Can you use cetirizine for food allergy?

Yes, cetirizine, an over-the-counter antihistamine, can relieve minor food allergy symptoms like itching, hives, or a runny nose. However, it is ineffective for treating severe allergic reactions like anaphylaxis, and emergency medical attention should be sought in such cases.

Does drinking water help food allergy?

Drinking water alone won’t cure a food allergy or neutralize an allergic reaction. However, staying hydrated could support overall health and help the body recover after an allergic response, but it is not a treatment for food allergy symptoms.

What should I eat after food allergies?

After experiencing a food allergic reaction, consuming foods known to be safe and do not contain the allergen you reacted to is essential. Stick to a balanced diet rich in fruits, vegetables, lean proteins, and whole grains, but always read labels and ask about ingredients to ensure the food doesn’t contain your specific allergen.


Photograph: microgen/Envato
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