The moment a person reacts to the contact, ingestion or inhalation of the proteins of a food, a food allergy reaction is triggered. In food allergy the reaction is to the proteins of this food.
What is food allergy?
Generally the allergy is due to a family of foods. We speak of cross-reactivity when a protein is present in different foods.
Other people may present allergy to respiratory proteins that are similar to food allergens as occurs in the pollen-fruit syndrome. The patient allergic to a pollen shows oral symptoms when consuming the food containing pollen-like proteins.
How does food allergy occur?
Food allergy procedures are different, but most often it is the one mediated by IgE type antibodies, which produces reactions on the spot. This type of reaction can cause even more severe reactions (anaphylaxis) and is capable of seriously endangering the life of the person in just a few minutes.
The same food allergen does not always cause the same picture and the intensity can change, so never be overconfident, even if the previous reactions were mild.
What are the symptoms of food allergy?
Allergic reactions mediated by IgE (allergy) can be skin symptoms such as swelling, hives and redness, digestive symptoms such as itchy lips and mouth, vomiting, respiratory symptoms such as sneezing, asthma or nasal congestion and anaphylaxis which manifests with low blood pressure and arrhythmia and is considered a life-threatening emergency.
What is food intolerance?
When there is a reaction to sugars (such as lactose, fructoseā¦) we would speak of an intolerance, and it manifests with specifically digestive symptoms (flatulence, diarrhea, abdominal pain), and is not associated with other allergic and severe symptoms.
In addition, there is another group of patients who have non-IgE antibody-mediated allergy with delayed reactions (between two hours to days after ingestion of the food). Immune cells and other immunoglobulins are involved. In recent years they have been called gastrointestinal allergies. We also find digestive manifestations and celiac disease, eosinophilic gastroenteropathies and gastroenteropathies induced by dietary proteins are part of this group.
Celiac disease is a chronic enteropathy (malabsorptive bowel disease). It is not an IgE-mediated disease; it has an IgA-mediated immune base. It is caused by gluten, a protein contained in wheat, barley, rye and oat flour or any of its varieties and hybrids (such as spelt, spelt, kamut and triticale).
It causes diarrhea, weight loss, abdominal distension and decreased food absorption. It is diagnosed by atrophy of the villi of the small intestine detected by intestinal biopsy.
Is allergy the same as intolerance?
Intolerances are similar to food allergies in that they affect only a small group of individuals and are due to a particular response of those individuals to the food, but are not mediated by an immune mechanism.
On the other hand, intolerances are due to modifications in the digestion or metabolism of food, generally due to enzymatic deficits, or to a particular susceptibility of some subjects to certain normal components of food (pharmacological). And it is usually due to sugars.
The most prominent example between allergy and intolerance is found in milk. Individuals who are allergic to milk are allergic because their immune system has generated IgE antibodies against some milk proteins. When these patients ingest milk, they manifest cutaneous symptoms and anaphylaxis. In subjects intolerant to milk, lacking intestinal lactase, the enzyme that digests lactose, typical digestive alterations are observed when milk is ingested.
How is a food allergy diagnosed?
Diagnosis consists of skin tests and, if necessary, determination of specific IgE in serum against food.
Sometimes these tests may not be definitive. In these cases it will be necessary to make use of oral tolerance tests in specialized allergy consultation, to confirm or rule out the diagnosis and give an appropriate dietary recommendation.
It is also important to resolve factors that may facilitate or aggravate food allergic reactions. These factors include physical exercise, taking non-steroidal anti-inflammatory drugs and the concomitant intake of alcoholic beverages.
How is a food intolerance diagnosed?
There are different types of tests depending on the intolerance observed. In the case of gluten intolerance, a specific immunological study is performed and the diagnosis is confirmed by intestinal biopsy. For patients with lactose intolerance or intolerance to fructose sugar present in fruits, specific breath tests are available.
What is the treatment of symptoms with food?
In mild allergic reactions antihistamines and/or corticosteroids are used. In severe reactions with systemic reactions, adrenaline should be used. And go immediately to the nearest emergency center and indicate the reason for the reaction to be evaluated on the spot.
When digestive reactions occur, there is no specific treatment, although rehydration is important in case of persistent vomiting and diarrhea, providing liquids and following a diet free of those foods recommended by the physician. The use of probiotics may also be useful as long as they do not contain the allergen.
The most effective treatment to prevent food allergy reactions is the strict elimination of the food involved from the diet, avoiding also traces of this food; in the case of having to make a very extensive elimination diet, it will be necessary to look for substitute foods in order to build a diet that covers the nutritional requirements of the affected person.
In cases of patients with intolerance to a food, the administration of this food should also be avoided. However, traces of the food responsible for the intolerance can be tolerated, since they do not produce severe symptoms. For lactose intolerant patients there are lactase preparations that help to metabolize lactose and allow its consumption in affected subjects.