Food Allergy

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What is Food Allergy?

A food allergy is a body reaction hypersensitive to a type of food. The cause of the activity of the symptoms after eating a particular kind of food is an immune mechanism. Factors that increase susceptibility to this type of allergy relate to habits in early life. People's organisms may be intolerant to certain foods, manifesting in diverse symptoms. The same allergens do not affect all people equally, so the same food will not cause a similar reaction in a person without a food allergy.

Food allergies manifest most commonly in the gastrointestinal tract, lungs, and skin. General or local symptoms prompt people to avoid foods that activate the immune response. Food allergies can be dangerous, posing a risk of anaphylactic shock. The diagnosis of allergies is based on clinical history, special tests, and examinations. Various therapeutic strategies can help patients with food allergies. Allergies can affect different types of food.

Some allergies become active after time, even with types of food that previously did not cause any symptoms. Common food allergies include allergies to fish and nuts. Despite the many studies that have provided new information on allergies in recent years, the diagnosis and treatment of this type of ailment remain a challenge. Learn more about food allergies. Find out about susceptibility factors, treatment methods, and more.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

Causes

Different types of allergies include food, inhalant, and contact allergies. In the case of a food allergy, the factor that causes symptoms is the entry of the allergen into the digestive system. Therefore, the leading cause of symptoms is an adverse immunological reactionTrusted Source. Food protein antigens are usually harmless and responsible for the response. Damage to the epithelial barrier leads to the release of inflammatory cytokines.

Scientific sources also state that food allergies are different from food intolerances. Food allergies have an immunological basis related to IgE antibodiesTrusted Source, while intolerances may involve the action of other types of antibodies, such as IgG, among others. IgE class antibodies are responsible for the involvement of different cells in the disease process.

Several factors influence the frequency, severity, and type of allergic symptoms. These factors are most commonly related to experiences and habits from early childhood to infancy. Aspects that may increase susceptibility to allergies include:

Genetic Predisposition

IgE antigens leading to sensitization usually develop in early childhood. Contact with the allergen induces IgE production in genetically predisposed individuals. Numerous studies based on family history of allergic diseases have shown that genetic factors influence food allergies.

Excessive Hygiene

The popular hygiene hypothesisTrusted Source also suggests that a lack of early childhood exposure to infections and microorganisms may increase susceptibility to food allergies. Excessive hygiene may cause an imbalance in the immune response. Increased exposure through contact with pets or the presence of older siblings may have a protective effect against allergic diseases.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

Vitamin D Deficiency

Another hypothesis is that vitamin D deficiency is associated with a predisposition to food allergies. This type of vitamin has proven immunoregulatory functions and is related to preventing allergic diseases. Studies have confirmed that infants with lower levels of vitamin D were at risk of peanut allergy. Therefore, low sun exposureTrusted Source leads to vitamin D deficiency, a factor in developing food allergies.

Impaired Skin Barrier Function

Various factors relating to infancy are linked to a predisposition to allergy. Another example is the dual allergen hypothesisTrusted Source, which posits that infantile eczema that disrupts skin barrier function may favor the occurrence of sensitization. Environmental exposure to allergens through the skin leads to a greater tendency to food allergies. This has to do with skin and intestinal exposure to the antigen.

Poor Diet

Some hypotheses involve dietary habits. One factor that increases the tendency to allergies is the presence of different strains of bacteria in the microbiota. In addition, the ‘false alarm' hypothesisTrusted Source assumes that a diet rich in glycation-inducing foods is related to food allergies. Elevated blood glucose levels lead to glycation, a reaction between sugars and proteins. Therefore, a diet rich in carbohydrates and sugars can trigger the mechanism for the development of allergies.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

Epidemiology

Recently, an increase in IgE-related food allergies has been noted in developed countries. It is, therefore, a severe and widespread public health problem. Some assume that this increase may be related to popularizing an unhealthy Western diet. In addition, as allergy is a disease of civilization, its growth may be related to improved personal hygiene and reduced family size. The reported prevalence of food allergy is 8%Trusted Source in children and 5%Trusted Sourcein adults.

Types

Food allergies vary because of the type of food causing the reaction. Many different foods can trigger allergy symptoms. The most common types of foods associated with food allergies include:

Dairy and Wheat Products

Various types of dairy and wheat products often cause allergies. InfantsTrusted Source most often develop food allergies to cow's milk and chicken eggs. On the other hand, older children and adults frequently develop allergies to wheat and soy, although this type of allergy can also occur in infants. However, allergies to dairy and wheat products usually subside over time as patients develop a tolerance.

Nuts and Fish

Common food allergies involve nuts, including peanuts, cashew nuts, hazelnuts, almonds, and more. Fish and shellfish also often cause allergic reactions. Unfortunately, allergies to nuts, fish, and seafood usually do not go away and persist throughout life.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

Symptoms

The type and severity of allergic disease symptoms can vary from case to case. The wide variety of symptoms has to do with the fact that allergy is not a single pathophysiological ailment. The intensity also depends on the type and amount of food that triggered the allergy. Symptoms usually appear quickly, within two hoursTrusted Source after eating the food. Groups of symptoms affect different areas, but symptoms can combine and co-occur. Food allergy symptoms include the following groups:

Skin Symptoms

Eating an allergenic food can result in skin symptoms, among the most common symptoms of oral allergic disease. Skin symptoms primarily include hives and itching. Redness and angioedema may also appear. Symptoms can affect different parts of the skin. Lesions can occur on the cheeks, the surface of the arms and legs, and the chest. Lips, tongue, or face swelling may also accompany them.

Digestive Symptoms

Food allergies are primarily associated with digestive system symptoms, which occur in about half of food allergy patients. These symptoms include nausea and vomiting, sometimes abdominal pain, and, in rare cases, diarrhea.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

Respiratory Symptoms

Respiratory symptoms are common with food allergies. Common symptoms of allergy include shortness of breath and wheezing. Patients may also experience itching, tightening of the throat, and coughing. Difficulty breathing can lead to coughing, a feeling of tightness in the chest, and even cyanosis. Symptoms can, therefore, resemble a sudden infection, as rhinitis, sneezing, and conjunctival erythema can also occur.

Cardiovascular Symptoms

In some patients, food allergy can manifest as cardiac organ symptoms. Symptoms include constriction of the blood vessels of the heart muscle and depression of the heart muscle. In addition, there may be chest pain and hypotension. Tachycardia and bradycardia, such as weak pulse and palpitations, have also been reported in some cases. In severe cases, collapsing shock may occur.

Nervous System Symptoms

These symptoms appear quite rarely during food allergy. Patients may exhibit sudden changes in behavior. The altered mental state manifests itself in the form of increased irritability, confusion, and anxiety. Tunnel vision or a reduced field of vision is also possible.

Diagnosis

The variety and uncharacteristic nature of food allergy symptoms can make diagnosis difficult. Diagnostic tools include history and diagnostic tests. It is also essential to identify the allergen that causes the allergic reaction.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

IgE Immunoglobulin Setermination

Serological tests to determine serum immunoglobulins can help confirm an IgE-related allergy. However, more than these tests are needed, as some food antigens do not have activity that the tests can highlight.

Skin Spot Tests (SPTs)

Skin tests are easy-to-perform tests that can detect cell degranulation. Based on the phenomenon of immediate hypersensitivity, skin spot tests are the primary diagnostic method in allergology. They involve applying an allergen to the skin and gently pricking it with a needle. In addition to the spot method, intradermal tests are also used.

Oral Provocation Tests

The most accurate allergy tests are oral provocation tests. Provocative tests are performed in allergy diagnostics to show that the suspected agent is responsible for causing disease symptoms. The tests can effectively confirm an allergy, but they come with risks, as exposure to the allergen during provocative testing can exacerbate the patient's condition.

Treatment

IgE-related allergic diseases are treated with various therapeutic methods. Some methods have a preventive basis, which involves avoiding the allergens that cause reactions. Other treatments involve various chemicals to relieve symptoms.

Food Allergy: What Is, Causes, Epidemiology, Symptoms, and Treatment

Elimination Diet

An allergy-matched diet should provide balanced nutrition for the patient. Prevention based on the elimination of allergy-causing foods is an essential long-term strategy that many patients opt for. A doctor can advise particular dietary guidelines. Products that cause allergies can be replaced with other substitutes. In most countries, possible allergens in foods are described on labels.

Allergen-Specific Immunotherapy

Immunotherapy, which modifies the course of the disease, is also possible in treating allergies. This type of treatment has long-lasting effects. The method is often used to treat respiratory allergies, but immunotherapy is also possible for food allergies. In such cases, oral, sublingual, and epidermal treatment is administered. This type of treatment works similarly to vaccinesTrusted Source. Desensitization involves repeated administration of an allergen vaccine to induce immune tolerance.

Pharmacotherapy

Supportive treatment for food allergies involves administering various types of drugs to patients. Medications reduce the intensity of symptoms but do not completely cure the allergy in the long term. They are tailored to the individual case. Commonly used medicines for IgE-related allergies include antihistaminesTrusted Source, epinephrineTrusted Source, and others.

Anaphylactic Shock

Allergies cause symptoms of varying intensity and, in some cases, can be dangerous. The most risky situation associated with food allergy is the induction of anaphylactic shock. Such cases are life-threatening for the patient and require medical intervention. A violent allergic reaction is characterized by rapidly releasing chemicals, such as histamine, which causes various symptoms.

Multiple triggers for anaphylaxis depend on the patient's sensitivity, but the most common are nuts, shellfish, or eggs. It is important to note that anaphylaxis usually does not occur at the first contact with an allergen but can occur after subsequent exposures.

Anaphylaxis can cause dangerous symptoms related to the respiratory and cardiovascular systems. These include increased allergic symptoms, which can be hazardous if the heart is short of breath. Severe cardiovascular and respiratory dysfunction can result in unconsciousness. In the case of anaphylaxis, the patient should always be taken to the hospital, even if they have already received an epinephrine injection.

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Summary

Food allergies are sudden reactions of the body to food ingested. Allergies have an immunological basis related to IgE antibodies. Factors that increase susceptibility to this type of allergy are mainly associated with habits in early life. Recently, food allergies have become a common problem that affects children more often. Various types of food can cause allergies, but common triggers include fish and nuts.

Food allergies are diverse, so they have a broad spectrum of symptoms. The most common are skin symptoms. Diagnosis is based on history and special diagnostic tests. There are various forms of treatment. Popular options include an elimination diet. Food allergies can be dangerous due to the risk of anaphylactic shock.

Sources

July 15, 2024
10 minutes read
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