GeneHealth - Your precision medicine

Food Allergy

Disease Details

Family Health Simplified

Buy Membership

Description: A food allergy is an abnormal immune response triggered by consumption of certain foods, leading to symptoms that can range from mild to severe, including anaphylaxis.
Type: Food allergies are typically classified as type I hypersensitivity reactions, which are IgE-mediated. The genetic transmission of food allergies shows a multifactorial inheritance pattern, where multiple genes and environmental factors contribute to the risk of developing the condition. There is a higher likelihood of food allergies occurring in individuals with a family history of allergies or atopic conditions such as asthma, eczema, or allergic rhinitis.
Signs And Symptoms: Food allergy symptoms occur within minutes to hours after exposure and may include:
Rash
Hives
Itching of mouth, lips, tongue, throat, eyes, skin, or other areas
Swelling (angioedema) of lips, tongue, eyelids, or the whole face
Difficulty swallowing
Runny or congested nose
Hoarse voice
Wheezing and/or shortness of breath
Diarrhea, abdominal pain, and/or stomach cramps
Lightheadedness
Fainting
Nausea
VomitingIn some cases, however, onset of symptoms may be delayed for hours.Symptoms can vary. The amount of food needed to trigger a reaction also varies.Serious danger regarding allergies can begin when the respiratory tract or blood circulation is affected. The former can be indicated through wheezing and cyanosis. Poor blood circulation leads to a weak pulse, pale skin and fainting.A severe case of an allergic reaction, caused by symptoms affecting the respiratory tract and blood circulation, is called anaphylaxis. When symptoms are related to a drop in blood pressure, the person is said to be in anaphylactic shock. Anaphylaxis occurs when IgE antibodies are involved, and areas of the body that are not in direct contact with the food become affected and show symptoms. Those with asthma or an allergy to peanuts, tree nuts, or seafood are at greater risk for anaphylaxis.
Prognosis: Prognosis for food allergies can vary depending on the age of onset, the specific allergen, and individual patient factors. In children, some food allergies (such as those to milk, eggs, and soy) are often outgrown, while others (such as peanut, tree nut, and shellfish allergies) are more likely to persist into adulthood. For adults, food allergies are typically lifelong. Managing food allergies involves strict avoidance of the allergen and immediate medical treatment in case of accidental exposure. With proper management, individuals with food allergies can lead normal, healthy lives, though the risk of severe reactions remains if they are exposed to the allergen. Regular follow-ups with a healthcare provider are essential for monitoring and adjusting management strategies.
Onset: The onset of food allergies can occur at any age but typically begins in childhood. Symptoms usually appear within minutes to a few hours after consuming the allergenic food.
Prevalence: The prevalence of food allergies varies depending on the region, population, and methodology used in studies. In general, food allergies are estimated to affect around 7% of children and about 2% of adults globally. These percentages can fluctuate with factors such as age, geographic location, and diagnostic criteria.
Epidemiology: Food allergies affect up to 10% of the worldwide population, and they are currently more prevalent in children (~8%) than adults (~5) in western nations. In several industrialized countries, food allergies affect up to 10% of children. Children are most commonly allergic to cow's milk, chicken eggs, peanuts, and tree nuts. While studies on adults with food allergy are not as abundant, surveys suggest that the most common food allergens for adults include fish, shellfish, peanuts, and tree nuts.Food allergies have become increasingly prevalent in industrialized/westernized nations over the last 2-3 decades. An estimated 15 million people currently have food allergies in the United States. In 1997, 0.4% children in the United States were reported to have peanut allergy, yet this number markedly rose to 1.4% in 2008. In Australia, hospital admission rates for food-induced anaphylaxis increased by an average of 13.2% from 1994-2005. One possible explanation for the rise in food allergy is the "old friends" hypothesis, which suggests that non disease causing organisms, such as helminths, could protect against allergy. Therefore, reduced exposure to these organisms, particularly in developed countries, could have contributed towards the increase.Children of East Asian or African descent who live in westernized countries were reported to be at significantly higher risk of food allergy compared to Caucasian children. Several studies predict that Asia and Africa may experience a growth in food allergy prevalence as the lifestyles there become more westernized.The prevalence of certain food allergies is suggested to depend partly on the geographical area and country. For instance, allergy to buckwheat flour, used for soba noodles, is more common in Japan than peanuts, tree nuts or foods made from soy beans. Also, shellfish allergy is the most common cause of anaphylaxis in adults and adolescents particularly in East Asian countries like Hong Kong, Taiwan, Singapore, and Thailand. Individuals in East Asia have further developed an allergy to rice, which forms a large part of their diet. Another example is that, out of 9 European countries, egg allergy was found to be most prevalent in the UK and least prevalent in Greece.
Intractability: Food allergies can be challenging to manage and, in some cases, may be considered intractable as there is currently no cure for food allergies. The primary method of managing food allergies involves strict avoidance of known allergens and prompt treatment of allergic reactions, often with medications such as antihistamines and epinephrine. While some children may outgrow certain food allergies, others may have lifelong sensitivities. Research is ongoing to develop better treatments and potential cures, such as oral immunotherapy and other desensitization methods.
Disease Severity: Disease severity for food allergies can range from mild to severe. Mild symptoms may include itching, hives, and stomach discomfort. Severe reactions, known as anaphylaxis, can involve difficulty breathing, a drop in blood pressure, and loss of consciousness, which require immediate medical attention. Severity can vary from one individual to another and can be influenced by the amount of allergen consumed, the person's sensitivity, and other factors.
Healthcare Professionals: Disease Ontology ID - DOID:3044
Pathophysiology: Conditions caused by food allergies are classified into three groups according to the mechanism of the allergic response:
IgE-mediated (classic) – the most common type, occurs shortly after eating and may involve anaphylaxis.
Non-IgE mediated – characterized by an immune response not involving immunoglobulin E; may occur some hours after eating, complicating diagnosis
IgE and/or non-IgE-mediated – a hybrid of the above two typesAllergic reactions are abnormal immune responses to certain substances that are normally harmless. When immune cells encounter the allergenic protein, IgE antibodies are produced; this is similar to the immune system's reaction to foreign pathogens. The IgE antibodies identify the allergenic proteins as harmful and initiate the allergic reaction. The harmful proteins are those that do not break down due to the strong bonds of the protein. IgE antibodies bind to a receptor on the surface of the protein, creating a tag, just as a virus or parasite becomes tagged. Why some proteins do not denature and subsequently trigger allergic reactions and hypersensitivity while others do is not entirely clear.Hypersensitivities are categorized according to the parts of the immune system that are attacked and the amount of time it takes for the response to occur. The four types of hypersensitivity reaction are: type 1, immediate IgE-mediated; type 2, cytotoxic; type 3, immune complex-mediated; and type 4, delayed cell-mediated. The pathophysiology of allergic responses can be divided into two phases. The first is an acute response that occurs immediately after exposure to an allergen. This phase can either subside or progress into a "late-phase reaction" which can substantially prolong the symptoms of a response, and result in tissue damage.Many food allergies are caused by hypersensitivities to particular proteins in different foods. Proteins have unique properties that allow them to become allergens, such as stabilizing forces in their tertiary and quaternary structures which prevent degradation during digestion. Many theoretically allergenic proteins cannot survive the destructive environment of the digestive tract, thus do not trigger hypersensitive reactions.
Carrier Status: Food allergies do not work the same way as genetic conditions with carrier status. They are adverse immune responses to specific foods and are not typically inherited in a manner that involves carriers of a gene. The development of food allergies can be influenced by a combination of genetic and environmental factors, but there isn't a "carrier" status as there is for conditions like cystic fibrosis or sickle cell anemia.
Mechanism: Food allergies are hypersensitive immune responses to certain foods. Their mechanisms involve both cellular and molecular processes:

1. **Mechanism**:
- **Sensitization**: Initially, an individual is exposed to an allergen (a protein in food). The immune system mistakenly identifies it as harmful.
- **IgE Production**: The body produces Immunoglobulin E (IgE) antibodies specific to that allergen.
- **Mast Cells and Basophils**: These IgE antibodies bind to receptors on mast cells and basophils, which are types of white blood cells.
- **Re-exposure**: Upon subsequent exposure to the same allergen, it binds to the IgE antibodies on mast cells and basophils.
- **Degranulation**: This binding triggers these cells to release chemicals, such as histamine, leading to allergy symptoms.

2. **Molecular Mechanisms**:
- **Antigen Presentation**: Dendritic cells process the allergen and present it to T-helper cells.
- **Th2 Cell Differentiation**: The allergen presentation favors the differentiation of naïve T-cells into Th2 cells.
- **Cytokine Production**: Th2 cells release cytokines such as IL-4, IL-5, and IL-13.
- **IgE Class Switching**: IL-4 and IL-13 promote B-cell class switching from producing IgM or IgG to producing IgE.
- **FcεRI Receptor Binding**: Produced IgE binds to high-affinity FcεRI receptors on mast cells and basophils.
- **Cross-linking of IgE**: Upon re-exposure, the allergen cross-links the IgE on the cells, triggering cellular activation and degranulation.
- **Release of Mediators**: This leads to the release of inflammatory mediators such as histamine, tryptase, and cytokines, causing the allergy symptoms like hives, swelling, and potentially anaphylaxis.

This intricate immune process results in the clinical manifestations observed in food allergies.
Treatment: The mainstay of treatment for food allergy is total avoidance of the foods identified as allergens. An allergen can enter the body by consuming a portion of food containing the allergen, and can also be ingested by touching any surfaces that may have come into contact with the allergen, then touching the eyes or nose. For people who are extremely sensitive, avoidance includes avoiding touching or inhaling problematic food. Total avoidance is complicated because the declaration of the presence of trace amounts of allergens in foods is not mandatory (see regulation of labelling).
If the food is accidentally ingested and a systemic reaction (anaphylaxis) occurs, then epinephrine should be used. A second dose of epinephrine may be required for severe reactions. The person should then be transported to the emergency room, where additional treatment can be given. Other treatments include antihistamines and steroids.
Compassionate Use Treatment: For food allergies, compassionate use treatments and off-label or experimental treatments are typically considered when conventional approaches such as strict dietary avoidance and emergency interventions with epinephrine are not sufficient. Some of these include:

1. **Oral Immunotherapy (OIT)**:
- **Description**: Gradually increasing the intake of the allergenic food to build tolerance.
- **Status**: Experimental but increasingly used; not universally approved.

2. **Epicutaneous Immunotherapy (EPIT)**:
- **Description**: Using a skin patch with small amounts of the allergen to desensitize the immune system.
- **Status**: Under investigation in clinical trials.

3. **Sublingual Immunotherapy (SLIT)**:
- **Description**: Placing small amounts of the allergen under the tongue to induce tolerance.
- **Status**: Experimental and subject to ongoing research.

4. **Biologic Therapies (e.g., Anti-IgE Monoclonal Antibodies like Omalizumab)**:
- **Description**: Using medications that target specific immune system components to reduce allergic reactions.
- **Status**: Off-label for food allergies; primarily approved for asthma and chronic urticaria.

5. **Helminth Therapy**:
- **Description**: Using controlled exposure to parasitic worms to modulate immune responses.
- **Status**: Highly experimental with limited studies.

These treatments should only be pursued under the guidance of a healthcare professional and within the context of clinical trials or specialized centers experienced in managing complex food allergies.
Lifestyle Recommendations: **Lifestyle Recommendations for Food Allergy:**

1. **Avoid Allergen Foods:** Carefully read food labels and ingredient lists to avoid allergens. Be aware of hidden sources of allergens in processed foods.
2. **Emergency Plan:** Always carry emergency medication such as antihistamines or an epinephrine auto-injector (EpiPen) if prescribed. Know how to use them and teach family or friends.
3. **Inform Others:** Communicate your food allergies to friends, family, coworkers, and restaurant staff to prevent accidental exposure.
4. **Cook Safely:** Use separate utensils, cookware, and preparation areas to avoid cross-contamination with allergens.
5. **Medical Alert ID:** Wear a medical alert bracelet or necklace to inform others of your allergy in case of an emergency.
6. **Education and Training:** Educate yourself about food allergies and consider joining support groups. Stay updated with the latest treatments and research.
7. **Dining Out:** Choose restaurants that accommodate food allergies and discuss your dietary restrictions with the staff before ordering.
8. **Meal Planning:** Prepare meals ahead of time to ensure safe and balanced nutrition. Bring safe snacks when traveling or attending events.
9. **Consult Professionals:** Regularly consult with healthcare providers, including allergists and dietitians, to manage your allergies effectively.
Medication: Medication for food allergy primarily involves the administration of antihistamines to alleviate mild to moderate allergic reactions. For severe allergic reactions, such as anaphylaxis, an epinephrine auto-injector (e.g., EpiPen) is essential. Healthcare providers may also recommend corticosteroids to reduce inflammation and prolonged symptoms. Always consult a medical professional for personalized advice and emergency action plans.
Repurposable Drugs: Research into repurposable drugs for food allergies is ongoing. As of now, no specific repurposed drugs have been conclusively approved for treating food allergies. Management of food allergies primarily involves avoiding the allergen and using medications like antihistamines or epinephrine in case of accidental exposure. However, several existing medications, such as omalizumab (originally for asthma), are being evaluated for their potential to treat food allergies by modulating the immune response.
Metabolites: Food allergies primarily involve immune system responses to specific proteins found in foods. Metabolites are not the primary focus in food allergies. However, it's important to consider that the ingestion of allergenic foods can result in the production and release of various biochemical mediators such as histamine, leukotrienes, and cytokines, which play a significant role in the allergic reaction.
Nutraceuticals: Nutraceuticals are products derived from food sources that offer additional health benefits beyond basic nutritional value. They may provide preventive and therapeutic effects for various conditions, including food allergies. Some commonly considered nutraceuticals for managing food allergies include probiotics, omega-3 fatty acids, and specific vitamins and minerals like Vitamin D and E, which may help modulate the immune response and reduce inflammation.

Regarding nanotechnology, it has potential applications in the diagnosis and treatment of food allergies. Nanoparticles can be used to develop sensitive diagnostic tools for detecting allergens at low concentrations and to create targeted drug delivery systems that improve the efficacy and safety of allergy treatments. This technology is still under research, but it holds promise for advancing food allergy management.
Peptides: In the context of food allergies, peptides are important because they are short chains of amino acids derived from proteins that can trigger immune responses. These peptides are recognized by the immune system of allergic individuals, leading to symptoms. Identification and characterization of allergenic peptides are crucial for diagnosing food allergies and developing treatments such as hypoallergenic foods. The term "nan" could be a typo or incomplete context; please provide additional details for a more specific explanation.