Allergies are an excessive immune response to a foreign compound. Its symptoms range from mild rashes, running nose, and watery eyes to life-threatening conditions known as anaphylaxis. How your body reacts to an allergen is called an “allergic reaction.” Allergens are any substance that causes the induction of allergies. An allergic reaction is the outcome of a series of events.

If you have allergies, your body produces allergic (IgE) antibodies the first time you get exposed to a specific allergen (such as pollen). These antibodies are responsible for locating allergens and assisting in their removal from your system.

As a result, a molecule known as histamine is released, causing allergy symptoms. Histamine was one of the first mediators of allergy to be discovered. According to studies, it plays a role in modulating allergic reactions.

You get a food allergy when your body creates a specific antibody to a particular food. An allergic reaction can happen as soon as minutes after consuming the meal, and the symptoms might be severe.

Shellfish, peanuts, and tree nuts are adults’ most prevalent food allergies. Milk, egg, soy, wheat, shellfish, peanuts, and tree nuts are allergens in youngsters. Research data shows that itching, hives, nausea, vomiting, diarrhoea, breathing difficulties, and mouth swelling are indications of a food allergy.

Types of Food Allergies

Food allergies are of three categories based on the symptoms and when they occur.

  • The most prevalent type of food allergy is IgE-mediated, caused by the immune system creating an antibody called immunoglobulin E. (IgE). After eating, symptoms appear seconds or minutes later. This sort of allergy carries a higher risk of anaphylaxis.
  • Food allergies caused by immune system cells other than immunoglobulin E are non-IgE food allergies. This allergy is difficult to detect since symptoms take a long time to manifest (up to several hours).
  • Food allergies mediated by IgE and non-IgE: some persons may suffer symptoms from both categories.

When do Food Allergies Develop?

Food allergies occur when the immune system, the body’s defence against infection, misinterprets food proteins as a threat. As a result, a variety of chemicals get discharged into the environment. These substances cause the symptoms of an allergic reaction.

As per studies and clinical trials, symptoms of a food allergy usually appear within minutes to two hours of ingesting the offending item. Symptoms may occur several hours later on rare occasions. Tingling or itching in the mouth are two of the most prevalent food allergy indications and symptoms.

Food allergies are more common in children but can occur at any age. It’s unclear why some adults develop allergies to foods they usually eat without issue. Adults are less likely than children to outgrow their food allergies.

Top Allergic Foods

The Big-8, which includes milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans, is a collection of the eight most common allergic foods.

According to the United States Food Allergen Labelling Act (FALCPA), these items account for over 90% of all product allergies in the country.


Milk is the most common allergen worldwide, and it accounts for the majority of food allergies in children. According to surveys and clinical findings, early childhood prevalence is between 2% to 6%. However, it is outgrown in up to 90% of cases by 6 years and only affects a few adults.

Milk allergy is due to an immunological response to a specific protein. Milk allergy is also known as lactose intolerance because it is one’s inability to digest lactose, a kind of sugar in milk.

Within the first hour after consuming milk proteins, most allergic people experience various symptoms in the gastrointestinal tract, the skin, and the airways. Caseins and the whey proteins (alpha-lactalbumin and beta-lactalbumin), the most abundant proteins in milk, are the most problematic milk allergens.


Eggs are a primary food component introduced into a child’s diet during the initial years of life. However, as per research, the frequency of egg allergy is particularly high in children. Egg allergy, like cow’s milk allergy, is commonly outgrown in the first six years of life.

Symptoms of hens’ egg allergy often emerge as digestive system reactions. The initial cutaneous (skin) reactions are frequently noticed within minutes after intake, although gastrointestinal symptoms can vary in onset, intensity, and duration. Furthermore, studies link ingestion of egg proteins to anaphylactic and respiratory symptoms.


While fish allergies are common worldwide, they are more common in areas where fish intake is high. Skin and gastrointestinal responses that occur quickly after intake are common indications of allergic reactions to fish. Severe systemic responses, including anaphylactic shock, have been reported by studies on occasion.

They make a significant contribution to human nutrition and the global economy.

Crustacean shellfish

According to the European Food Safety Authority, crustacean shellfish allergies primarily affect older children and adults, particularly in areas where consumption is high.

In crustacean shellfish allergy, people react to a variety of crustacean shellfish. Still, they can also respond to molluscan shellfish and edible land snails, thanks to tropomyosin, the primary shellfish allergen.

Shrimps, prawns, crabs, and lobsters are the most important members of the crustacean shellfish family for human consumption.

Tree Nuts

Nuts are one of the most common dietary allergies in the world. The group includes nuts like Brazil nut, chestnut, hazelnut, pine nut, walnut, etc. Nuts are fruits and legumes (e.g., almond, pecan nut, coconut, cashew, peanut).

Nuts are one of the most potent allergenic foods in terms of the amount necessary to induce an allergic reaction and the severity of the response.

The frequency of nut allergy in the general population in the United States is estimated to be around 1.1%, according to a list issued by governmental authorities after extensive surveys and research. Nut allergies frequently cause severe multisystemic and respiratory symptoms and catastrophic anaphylactic reactions.


Legumes are important crop plants, accounting for more than 25% of global primary crop production. Legumes are high in nutritional content (high-value proteins and oils), but unfortunately, they can cause many allergic reactions, as suggested by studies.

For example, peanuts are one of the strong and most common allergic foods. Proteins linked to bean allergies are primarily from the seed storage protein family (albumins, globulins, prolamins). They are frequently found in large quantities and retain their allergenicity when heated.


Wheat and other cereal allergy reactions are most common in infants and typically disappear within the first few years of life. IgE-mediated allergy to cereals can cause modest local responses on the skin or in the gut and more serious, often life-threatening anaphylactic events.

Wheat allergy can also include bakers’ asthma due to occupational exposure to grain flour dust. According to research, wheat-dependent exercise-induced anaphylaxis (WDEIA) is a rare IgE-mediated allergy caused by wheat ingestion accompanied by cofactors like exercise.

Rice is generally tolerable for people sensitive to wheat-related crops (barley, oats, and rye). Rice allergies are uncommon in Europe and America, but they may be more common in Asia.


Soybean and its derivatives are present in culinary items, both as food (e.g., tofu) and technological assistance (e.g., emulsifiers, texturisers). However, soy allergies are significantly less common than peanut allergies.

The symptoms of a soybean allergy are similar to those of a peanut allergy, ranging from minor reactions to life-threatening system reactions. Although it is most common in infants and children, it can appear at any age.

Lupin is becoming more widely used as a culinary ingredient, and its flour can act as a soy or wheat alternative in processed meals. However, Lupin is closely related to peanuts, and some people allergic to peanuts may react to it. Localised oral and cutaneous reactions, as well as acute asthma and anaphylactic reactions, are among the symptoms.

The HealthifyMe Note

A food allergy occurs when the immune system overreacts to food proteins. Usually, symptoms of food allergy develop very soon after consuming the food. Peanuts, tree nuts, milk, eggs, wheat, sesame, fish, shellfish and soy are the most common food allergens.

Treating Food Allergies

The FDA advises the food industry, consumers, and other stakeholders on the best methods for assessing and managing allergy dangers in food. The FDA also conducts inspections and sampling to ensure that products’ major food allergens are correctly labelled.

When there are concerns, the FDA works with companies to recall products and issue public notices to inform consumers. Furthermore, the FDA has the right to confiscate and remove illegal products from the market and reject the entry of imported goods.

Treatment always remains the second choice. Due to its rapid start of action (15–60 minutes) and widespread availability, diphenhydramine has become the antihistamine of choice for acute food allergy responses.

However, epinephrine remains the first-line therapy for anaphylaxis, studies suggest. In addition, drowsiness is a common diphenhydramine side effect, which, in clinical experience, might make assessing a patient being treated for an acute allergic food reaction more difficult.

Cetirizine is a second-generation antihistamine. It has a similar start to diphenhydramine but a longer duration of effect. When treating acute food allergies, cetirizine and diphenhydramine have similar efficacy and commencement of an action.

Cetirizine is an excellent therapeutic choice for acute food allergies since it has similar efficacy but a longer duration of action than diphenhydramine. Doctors recommend the use of an auto-injector.

The HealthifyMe Note

Epinephrine, followed by diphenhydramine, is the antihistamine of choice for food allergies. Cetrizine is another antihistamine used for treating acute food allergies.


You get a food allergy when your body creates a specific antibody to a particular food. An allergic reaction is the outcome of a series of events.

Shellfish, peanuts, tree nuts, and milk are the most prevalent food allergies and thus make their way to Big-8. The Big-8 is a collection of the eight most common allergic foods. Labelling of the Big-8 is also necessary by EU, Canadian, Japanese, and Australian/New Zealand rules.

Milk and eggs account for the majority of food allergies in children. Crustacean shellfish allergy is more common in older children and adults, particularly in high consumption areas. Nuts are also one of the most potent allergenic foods.

There is no cure for food allergies, but their symptoms can decrease due to drugs like cetirizine and diphenhydramine. The use of an auto-injector is preferable.

Frequently Asked Questions (FAQs)

Q. How do I know what I am allergic to?

A. A skin prick test, often known as a puncture or scratch test, detects acute allergic reactions to up to 50 chemicals simultaneously. This test discovers pollen, mould, pet dander, dust mites, and food allergies. The test site is commonly the forearm in adults. You may find out what you’re allergic to right at home by taking dust samples and getting a thorough report on what allergens are around you at your home. When combined with blood testing, the kit can determine which allergens you need to eliminate from your household.

Q. What are food allergies called?

A. Food allergies are also known as oral allergy syndrome. Certain fresh fruits and vegetables, nuts and spices, might provoke an allergic reaction in this condition, causing the mouth to tingle or itch. A food allergy is also known as food hypersensitivity in medical jargon.

Q. What are common food allergy reactions?

A. An allergic reaction to a specific meal may be uncomfortable but not life-threatening for some people. However, an allergic food reaction can be distressing. Symptoms of food allergies usually appear within minutes to two hours of ingesting the offending item. However, symptoms can sometimes be delayed for several hours.

The following are the most common food allergy indications and symptoms:

  • Tingling or itching in the mouth
  • Eczema, hives, or itching
  • Lips, cheek, tongue, and throat swelling, as well as swelling in other areas of the body
  • Wheezing, nasal congestion, or breathing difficulties
  • Pain in the abdomen, diarrhoea, nausea, or vomiting
  • Lightheadedness, dizziness, or fainting

Q. Can food allergies go away?

A. There is no one-size-fits-all solution. Milk, egg, wheat, and soy sensitivities may fade, but peanut, tree nut, fish, and shellfish allergies are usually permanent. The only method to avoid a food allergy reaction is to avoid the food items completely. Although peanut, tree nut, fish, and shellfish allergies are frequently considered lifelong allergies, some people outgrow them. It could take a few hours to a few days for them to vanish. However, if you continue to get exposed to the allergen, such as during pollen season in the spring, allergy reactions might persist for weeks or months.

Q. Do food allergies get worse with age?

A. Food allergies are becoming a significant health issue among the elderly. Age-related changes significantly impact the innate and adaptive immune systems, and older adults are more likely to develop food allergies as their immune systems age. However, depending on the age of development and the type of allergy, food allergies can go away in certain circumstances. For example, allergies to soy, wheat, milk, and eggs develop in childhood and may be outgrown, while allergies to tree nuts, peanuts, and shellfish (mainly in adults) remain lifelong. Therefore, your allergies may shift and change at different times in your life.

Q. What foods cause itching?

A. Peanuts, wheat, eggs, cow’s milk, soy, and shellfish are among the most prevalent causes of itching. The irritation generated by certain meals and subsequent scratching might cause dermatitis flare-ups or worsen symptoms. An IgE-mediated food allergy is the most pervasive type of allergic itching. 

Q. How long does a food allergy reaction last?

A. The rash should generally go away in a day or two. The second wave of food allergy symptoms can develop up to four hours following the initial reaction, though this is uncommon. Contact your doctor if you believe your food allergy rash has become infected. Hives caused by meals usually only last a few days. They typically vanish in less than 6 hours.

Q. What is the best antihistamine for food allergies?

A. Epinephrine remains the first-line therapy for anaphylaxis, according to studies. Cetirizine is an excellent therapeutic choice for acute food allergies since it has similar efficacy but a longer duration of action than diphenhydramine. The use of diphenhydramine is limited due to the side effects.

Q. How do you get rid of food allergies?

A. There is presently no cure for food allergies, and the only method to avoid a reaction is to avoid the food to which you are allergic. However, one can reduce the risk of significant health repercussions by rapidly diagnosing and controlling allergic responses to food if they occur. Antihistamines can also help alleviate the symptoms of a minor allergic reaction.

Q. How can you find out if you have an allergy? What are the two types of allergy tests?

A. You can find out that you have an allergy by following two tests – 

  • Skin Prick Test: A tiny needle is used to prick the skin of your forearm or back with 10 to 50 different possible allergens in a skin prick (scratch) test.
  • Intradermal Skin Test: If your skin prick test findings are negative or equivocal, you may need an intradermal skin test.

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