An allergy is an adverse, hypersensitive reaction of the immune system to a food or substance introduced to the body. Allergies may present themselves in the form of food e.g., nuts and seafood, or from an external substance e.g. animal fur or dust that is introduced into the body through the mucous membranes of the eye, nose or mouth. When detected by the immune system as a hostile agent, cells of the lymphoid, myeloid families divide, mature and migrate to produce an inflammatory response. There are many theories as to why individuals produce this heightened response, however little if any have been scientifically validated. Some have suggested a genetic influence through subgroups of the population e.g. Asians have a genetic intolerance to lactose which produces mild allergic reactions.
Food allergies are more often than not discovered by chance during childhood, and can be avoided by simple changes to an individual’s diet. If symptoms of allergies occur without a specific cause being known, a visits to your local GP can allow investigation into a range of common allergens, where they are found and the best way to avoid them.
Allergies produce a range of symptoms, with mild symptoms including itching, swelling of the face (anglodema) and vomiting. In more serious conditions, individuals may suffer from anaphylaxis, which if left untreated may lead to death. Anaphylaxis produces symptoms of dizziness, loss of consciousness and constriction of the muscles of the upper respiratory tract leading to severe hypoxia. Wheezing is a common sign, caused by constriction of the bronchial muscles in the throat. On an immunological level, immunoglobulins (Ig) bind to the antigen (the foreign material provoking the reaction). When this Ig-antibody complex is formed, there is subsequent activation of receptors found on the cell surface of white blood cells. This leads to the downstream activation and release of histamine. Histamine produces constriction of bronchial smooth muscle, triggers vasodilation of blood vessels and causes heart muscle depression. In the severe case of anaphylaxis, epinephrine/adrenaline must be administered to produce vasodilation of the respiratory tract, allowing the flow of oxygen into the alveoli of the lungs. Less severe conditions may be treated using anti-histamines. Anti-histamine drugs target one of two histamine receptors, H1 or H2, preventing its release from cells and its subsequent effects.
Thanks to the medical intervention found in today’s society, individuals can rest assured that when allergies occur, treatment is readily available over the counter or by medical professionals. And thanks to the government’s policy on reducing the potential risks of allergic reactions to foodstuffs, a comprehensive list of ingredients are found in supermarket products and in restaurants.