Millions of people live with food allergies. Chances are, you are either one of them or know someone who is. According to the Centers for Disease Control and Prevention, food allergies affect 4–6% of children and about 4% of adults (Cosme-Blanco, Arroyo-Flores, and Ale, 2020).
An adverse reaction after eating a particular food may be the result of either a food intolerance or a food allergy. Although the symptoms can be similar, the underlying mechanisms are different, and each condition requires a different approach. Food intolerance does not involve the immune system and is defined as the inability to properly digest a particular food or food ingredient. A food allergy, by contrast, is a mild to severe immune response triggered by contact with a food or one of its components.
Causes and symptoms of food allergies
In people with food allergies, the immune system activates certain cells that trigger the release of immunoglobulin E (IgE) antibodies, which are responsible for targeting the food—or the specific substance within that food—that causes the allergic reaction (Gargano, Appanna et al., 2021).
In adults, the most common allergenic foods are peanuts, tree nuts (including walnuts and pecans), fish, and shellfish such as lobster, shrimp, and crab. In children, proteins found in eggs, cow’s milk, peanuts, tree nuts, wheat, and soy are among the most frequent triggers of food allergies. In infants, the early introduction of highly allergenic foods may lead to food protein-induced enterocolitis syndrome (FPIES), a condition characterised by vomiting, bloody diarrhea, and dehydration. FPIES is a medical emergency that requires hospitalisation and specialised treatment (Rotella, Lee et al., 2023).
A food allergy can also develop in people who have eaten a particular food for years without any previous problems. It is not possible to predict whether a parent’s food allergy will be inherited by their child. Allergic reactions are more common in infants and young children. Most symptoms develop within a few minutes to two hours after ingestion, although delayed reactions may occur four to six hours later, as in the case of red meat allergy. In general, the symptoms include hives (a skin rash), itching, a tingling sensation, difficulty breathing, wheezing, repeated coughing, difficulty swallowing, swelling of the lips and tongue, swelling of the throat (which can impair breathing or speech), nausea, vomiting, diarrhea and/or abdominal pain, dizziness, pale or bluish skin (cyanosis), a weak pulse, or anaphylactic shock. Anaphylactic shock is the most severe type of allergic reaction. It is life-threatening because it can impair breathing, cause a sharp drop in heart rate and blood pressure, and disrupt normal heart function. Anaphylaxis can develop within seconds of exposure to the allergen, which is why a dose of epinephrine should be administered as quickly as possible.
Diagnosis and treatment
The diagnosis of a food allergy should be made by a specialist in allergy and immunology and can be established using several methods. Skin tests involve applying a small amount of the suspected allergen to the patient’s skin and observing the reaction. The appearance of a localised reaction, such as swelling or redness, confirms the presence of an allergy. For patients with more sensitive skin, blood tests are used to measure the levels of antibodies directed against the suspected food allergen. Oral food challenge tests involve exposing the patient to the suspected food in a controlled, gradual manner under the close supervision of a physician, who can intervene immediately if an allergic reaction occurs (Mendonca and Andreae, 2023).
The primary way to prevent a food allergy reaction is to eliminate the food that triggers it from the diet. There are no natural remedies that have been proven to treat food allergies. In the case of a mild allergic reaction, over-the-counter antihistamines may be used. These medications can relieve symptoms such as itching and skin rashes but are not recommended for severe allergic reactions. Severe food allergy reactions require immediate medical attention and the emergency administration of epinephrine, which is the first-line treatment for anaphylaxis (Krajewski and Krajewski, 2022). Immunotherapy is an alternative treatment for certain food allergies and involves gradually exposing the patient to the specific allergen in order to increase tolerance and reduce the severity of allergic reactions (Johnson-Weaver, 2023).
Bibliography
- Cosme-Blanco, W., Arroyo-Flores, E., și Ale, H. (2020), “Food allergies”, in Pediatric in Review, vol. 41, no. 8, pp. 403–415.
- Gargano, D., Appanna, R., et al. (2021), “Food allergy and intolerance: A narrative review on nutritional concerns”, in Nutrients, vol. 13, no. 5, art. no. 1638.
- Johnson-Weaver, B. T. (2023), “Preclinical evaluation of alternatives to oral immunotherapy for food allergies”, in Frontiers in Allergy, vol. 4, art. no. 1275373.
- Krajewski, G. S., and Krajewski, T. (2022), “Evaluation and management of food allergies in the emergency department”, in Emergency Medicine Clinics of North America, vol. 40, no. 1, pp. 57–67.
- Mendonca, C. E., and Andreae, D. A. (2023), “Food allergy”, in Primary Care, vol. 50, no. 2, pp. 205–220.
- Rotella, K., Lee, A. S. E., et al. (2023), “Food protein-induced enterocolitis syndrome (FPIES) to peanut: Characteristics and long-term outcomes of a large cohort”, in The Journal of Allergy and Clinical Immunology: In Practice, vol. S2213-2198, no. 23, art. no. 01141-8.