Food Allergies: Symptoms, Diagnosis, Treatment

What are the symptoms of food allergies ?

For further information: Food Allergy Symptoms


The symptoms of food allergies are quite variable in terms of location and intensity; typically involves the gastrointestinal , respiratory and skin systems .

The mast cells , which upon interaction with IgE release histamine (molecule responsible for many effects associated with allergic manifestation), are especially abundant at the level of organs such as the nose , throat, lungs , skin and stretch gastro-intestinal .

The signs and symptoms of food allergy, which fortunately are annoying but not always so dangerous, on average arise from a few minutes to an hour after the end of the meal.Not only between different subjects, but also for the same person, they can vary from mild to severe. Despite having suffered only from one or more light allergic attacks, there is the possibility of running into a serious or very serious reaction.
The symptoms of food allergies can be summarized as follows:

  • Vomitingand / or stomach cramps
  • Urticaria
  • Shortness of breath
  • Wheezing
  • Repetitive cough
  • Shock or circulatory collapse
  • Hoarsenesswith swallowing problems
  • Swelling of the tongue, which affects the ability to speak or breathe
  • Weak pulse
  • Pale or bluish discoloration of the skin
  • Dizzinessor feeling faint
  • Anaphylaxis.

Note : Allergic reactions can affect different parts of the body at the same time, such as the stomach and skin, with abdominal pain and cramps associated with a skin rash.

What is anaphylaxis?

Anaphylaxis is the most fearful consequence of a food allergy is anaphylactic shock , which in the most serious forms can lead to the occlusion of the respiratory tract, to coma and to the death of the individual and therefore requires early intervention. with epinephrine or adrenaline .


Most common symptoms of a food allergy Symptoms associated with anaphylactic shock or anaphylaxis
·                                 Itching in the mouth and pharynx

·                                 Hives, itchy skin or eczema

·                                 Swelling of the lips , face, tongue, throat or other parts of the body

·                                 Asthma , nasal congestion or breathing problems

·                                 Abdominal pain , diarrhea , nausea or vomiting

·                                 Vertigo, fainting, migraine , dizziness

·                                 Constriction of the respiratory tract, resulting in difficulty breathing

·                                 Shock, with a severe drop in blood pressure , pallor

·                                 Anxiety, palpitations , sweating

·                                 Vertigo, fainting, coma


More frequent symptoms in children

In allergic children, the most frequent reactions (70%) concern the gastrointestinal system, but skin (24%) and respiratory (6%) disorders can also occur. The most fearful consequence is anaphylactic shock, which can often be triggered by minimal quantities of food.

Time of Onset

How long does it take for symptoms to appear?

Most food allergy symptoms appear within two hours of ingestion; they are often enough in minutes or even seconds. In some rare cases, the reaction may be late and appear four to six hours later.

Late allergic reactions

Late allergic reactions occur mainly in children in the form of skin eczema. Interested in:

  • People affected by a rare allergic form to red meatcaused by the tick bite
  • People with food protein-induced enterocolitis syndrome (FPIES), a severe gastrointestinal reaction that occurs two to six hours after ingestion of milk, soy , cereals, and some solid foods . It mainly affects weaning infants . FPIES causes repeated vomiting and diarrhea (even bloody) which can lead to dehydration .

Allergies and Overweight

Do food allergies make you fat?

The belief that food allergies promote overweight and obesity has no scientific basis. If anything, the opposite is true for behavioral and non-metabolic reasons; in fact, the limitation of food choices has long been known as one of the most effective strategies to combat overweight.
The mice fed automatically, according to “self service” mechanisms, respond differently depending on the number of foods available. When the mouse is fed with only one type of food, even if it is particularly appreciated, it is perfectly able to stop taking it. On the contrary, when the same animal can choose between various and palatable foods, it eats more than necessary and gets fat.


Diagnosis of food allergies

The diagnosis of food allergy is based on various clinical tests and on a careful analysis of the patient’s clinical history . In general, it is preferable to start with skin tests, evaluating the appearance of allergic reactions after administration of antigens of different nature under the skin . Once the food or type of allergen in question has been identified, specific in vitro tests, such as RAST or ELISA, can be performed to find out which protein fragments are responsible for the allergy.
The diagnostic techniques available today are numerous, with varying degrees of complexity and in continuous evolution, in order to obtain innovative methods with greater reliability and reliability. In many cases, in fact, the search for the allergen is hindered by various factors, first of all that of co-sensitization.

Complications of the diagnosis

Non-diagnosable food allergies

More and more frequent are allergic people who test negative to common diagnostic tests; this phenomenon occurs particularly when the individual is sensitive to different substances, but to a slight extent, and therefore manifests allergic reactions only when he is exposed to several allergens at the same time. It should also be emphasized that these allergies cause attenuated symptoms, further complicating their identification.

Cooking food and food allergies

It can also happen that a person is allergic to raw food but not to cooked food, since many allergens, being of a protein nature, are inactivated by heat. Be careful though, cooking is generally not enough to make a food harmless. Allergens can be of various types; if the allergy concerns a peptide that is very sensitive to denaturation, cooking is more likely to be effective. On the contrary, if the protein segment is very resistant (and abundant), or if the cooking is not intense or prolonged, it does not protect in any way from the danger of allergic reaction.

Complexity of the recipe and food additives

Another factor that can complicate the diagnostic identification of the allergen is represented by the use of complex foods , that is, made up of many ingredients and food additives.
Once the allergy has been diagnosed, the food or foods in question must be eliminated from the diet.


by Abdullah Sam
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