Allergic reactions

Allergic reactions can take many forms, depending on which systems are affected.

Respiratory system

• Difficulty breathing
• Throat tightness
• Rhinitis (inflammation of the nasal passages)
• Wheezing

Cutaneous system (skin)

• Hives
• Swollen lips
• Swollen tongue, face or both

Cardiovascular system

• Drop in blood pressure
• Cardiac arrest
• Arrythmia

Gastrointestinal system

• Cramps
• Nausea 
• Vomiting
• Diarrhea
• Difficulty swallowing 

An allergic reaction can also cause confusion, dizziness, loss of consciousness or anaphylaxis.

Anaphylaxis is a severe, generalized allergic reaction. If left untreated, it can lead to death. Out of all the possible ways that allergies can manifest themselves, anaphylaxis requires the most urgent intervention.

This severe reaction affects the respiratory, cutaneous (skin), cardiovascular and digestive systems all at once. Anaphylaxis is characterized by many of the symptoms mentioned above, which can appear alone or in combination. The reaction can start with:

• Itching
• Hives
• Vomiting
• Diarrhea
• Swollen lips or face

In the most severe cases, such as a blocked throat that makes it hard to breathe, anaphylaxis can lead to a loss of consciousness or death.

Anaphylactic reactions are unpredictable. A person may present symptoms that progress in very different ways from one episode to the next.

Anaphylactic shock occurs when the reaction triggers a drop in blood pressure.

Oral allergy syndrome is an allergic reaction that is usually limited to the areas around the mouth (mouth, lips and throat). It can be triggered by eating fruits, vegetables, nuts and seeds. It affects those who are allergic to certain types of pollen.

People with oral allergy syndrome can experience itching or burning sensations. They may also have symptoms that affect other systems of the body. Symptoms appear immediately or shortly after exposure to the allergen.

Most reactions are benign and short-lived. However, more serious reactions may occur, such as hives or swelling of the mouth, pharynx or trachea. In rare cases, serious generalized allergic reactions may occur, potentially leading to anaphylactic shock.

These reactions are usually caused by raw foods, as cooking eliminates the substances that may cause the syndrome. 

Not all reactions to fruits and vegetables are necessarily linked to oral allergy syndrome. Some fruits and vegetables, such as oranges, tomatoes, apples, grapes and strawberries, can cause allergic reactions. These fruits can also trigger rashes, hives or diarrhea.

This disease is an immune response to the gluten protein in certain grains (oats, wheat, spelt, Kamut, barley, rye, triticale). Reactions to gluten differ from reactions caused by food allergies. 

Celiac disease mainly causes digestive symptoms. These symptoms lead to poor absorption of nutrients such as protein, iron and calcium.

Visit the Celiac Canada  and Fondation québécoise de la maladie cœliaque  websites.

Chemical sensitivities are characterized by an undesirable reaction to a substance, such as sulfites. If a sensitive person ingests this substance, they could experience allergy-like symptoms. These symptoms may be minor, but they could also be as serious as asthma attacks or even anaphylaxis.