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Allergies, intolerances and anaphylaxis
Allergies, intolerances and anaphylaxis

Allergies, intolerances and anaphylaxis

Date: April 03, 2023

A distinction must be made before introducing the subject. With the term Allergy in fact, we mean an anomalous reaction, in which our immune system is involved, while the term intolerance means an adverse, non-toxic and non-immunological reaction, due to an enzyme deficiency or a metabolic defect.

Allergies, in fact, occur when our immune system reacts to a foreign substance, for example:

  • pollen;
  • bee venom;
  • pet hair;
  • foods.

Our immune system produces substances known as antibodies.

When we are born with or develop allergies during our lifetime, our immune system then produces antibodies, which identify a particular allergen as harmful, even if it is not. The antibodies therefore label as "dangerous" something that is apparently harmless to our body, and act accordingly, inducing an inflammatory process.

When you come into contact with the allergen, your immune system's reaction can inflame your skin, sinuses, airways, or digestive system.

The severity of allergies varies from person to person, and can range from a mild irritation to anaphylaxis, a potentially life-threatening emergency.

Although most allergies cannot be cured, treatments can help relieve allergy symptoms.

What areas of the body can be affected?

People experience different symptoms, depending on the affected allergen and where it enters the body. Allergic reactions can also involve several parts of the body at the same time, and among these:

  • nose;
  • eyes;
  • paranasal sinuses;
  • throat.

When allergens are inhaled, the release of histamine causes the lining of the nose to produce more mucus, becoming inflamed. The nose begins to itch and violent sneezing may occur. The eyes may start to water, and some people may get a sore throat.

Lungs and chest

Asthma can be triggered during an allergic reaction. When an allergen is inhaled, the lining of the passageways in the lungs swell and makes breathing difficult.

Stomach and intestines

Foods that commonly cause allergies include peanuts, seafood, dairy products and eggs. Cow's milk allergy in infants can occur and can cause eczema, asthma, colic and stomach upset. Some people cannot digest lactose (milk sugar), due to enzymatic or metabolic defects. In this case we speak of lactose intolerance, which causes stomach upset, but which should not be confused with an allergy.


Skin problems that can be triggered by allergies include atopic dermatitis (eczema) and hives.

Certain types of allergies, including those to food and insect bites, can trigger a serious reaction known as anaphylaxis. A life-threatening medical emergency: Anaphylaxis can cause shock.

Physical reactions to certain foods are common, but most are caused by food intolerances rather than allergies. A food intolerance can cause some of the same signs and symptoms as an allergy, so it's often common to confuse the two.

A true food allergy causes an immune system reaction that affects numerous organs in the body . It can cause a variety of symptoms and in some cases, an allergic reaction to food can be even serious or life threatening. Conversely, the symptoms of food intolerances are generally less severe and often limited to digestive problems.

If we have a food intolerance, we may be able to eat small amounts of the offending food without experiencing any problems, and even be able to prevent a reaction. Per example, being lactose intolerant, we may be able to drink lactose free milk or take lactase enzyme pills (Lactaid) to aid digestion.

Causes of food intolerance include:

  • Absence of an enzyme needed to fully digest a food. Lactose intolerance is a common example (lack of the enzyme lactase).
  • Irritable Bowel Syndrome . This chronic condition can cause cramping, constipation and diarrhea.
  • Sensitivity to food additives . Per example, the sulphites used to preserve nuts, canned goods and wine can trigger asthma attacks in sensitive people.
  • Recurring stress or psychological factors . Sometimes the mere thought of food is enough to cause discomfort. The reason is not fully understood.
  • Celiac disease . Celiac disease has some characteristics of a true food allergy, because it affects the immune system. Symptoms often include gastrointestinal problems, and others unrelated to the digestive system, such as joint pain and headaches. However, people with celiac disease are not at risk of anaphylaxis. This chronic digestive condition is triggered by the consumption of gluten, a protein found in wheat and other grains.

Some major food allergies may put you at risk of a life-threatening reaction (anaphylaxis), even if your past reactions have been mild. It would be useful and necessary, if you suffer from allergies, to carry an emergency injection of adrenaline, for any emergency self-treatment.



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