Allergies: A Complex Health Issue
Allergies, whether food, respiratory, skin, or drug-related, affect people of all ages and manifest in highly varied ways, ranging from mild symptoms to severe reactions. Their complexity stems from the fact that they involve the immune system, that triggers are numerous and sometimes difficult to identify, and that each individual can react differently to the same substance.
Furthermore, treatments are not always curative: they often aim to alleviate symptoms or avoid allergens, which can be restrictive in daily life. This management therefore requires constant vigilance and continuous adaptation, both for those affected and for healthcare professionals.
To better understand these realities and answer the most frequently asked questions, the FAQ below demystifies some essential points related to allergies:
What is an allergy?
Allergy, or an allergic reaction, is an abnormal, excessive response of the immune system. This reaction follows a previous contact with a foreign substance (the allergen), mistakenly considered dangerous by our cells. Thus, a substance that is completely harmless to some can cause an allergic reaction in a sensitized person.
Are there causes for allergic phenomena?
Factors implicated in the onset of allergic manifestations:
Family predisposition, also known as "atopic ground," determines the risk of allergic manifestations in children:
- If neither parent is allergic → 15%
- If 1 of the 2 parents is allergic → 40%
- If both parents are allergic → 60%
- If both parents + 1 close family member is allergic → 75%
The evolution of our lifestyle, our habitat, and climate change.
- We travel more and more
- We eat unusual foods
- We plant all kinds of plants in our gardens
- Increase in the number of pets
This latter factor has led to a significant increase in the incidence of allergies in recent decades.
Air pollutants do not cause allergic phenomena, but they appear to be aggravating factors.
How is allergy diagnosed?
As soon as evocative signs appear, such as a runny nose, itchy eyes, or repeated sneezing, medical care by an allergist is essential. It aims to establish the diagnosis of the allergy and identify the allergen(s) responsible for the reaction, in order to implement effective treatment specific to the allergen in question.
Patient interview or history
This rigorous and thorough interview must confirm the hypothesis of allergy and make it possible to draw up an initial list of the allergens responsible for the symptoms presented. Everything will be scrutinized:
- History of symptoms (onset, nature, periodicity, triggering factors, etc.)
- Family history of allergy, as well as personal history
- General environment
- Lifestyle, living spaces, eating habits
- Professional and leisure activities
Several consultations may be necessary to evaluate everything, but this assessment is essential for diagnosis and identification of the allergen(s) involved.
Clinical examination
General examination and targeted examination of organs often affected by allergies (skin, lungs, nose, bronchi). It allows the allergist to assess the repercussions of the allergy. It guides further investigations that may be necessary (functional exploration in asthma, etc.).
What are the different allergy tests?
Skin tests
The skin is lightly scratched through a drop of allergen previously placed on the arm.
Biological tests (blood screening)
In some cases, a blood sample is required for this laboratory test.
Provocation tests
Only performed if there is still doubt. They must be carried out under close medical supervision.
How can allergies be treated?
Treating an allergy means addressing both its symptoms and its cause.
Allergen avoidance
By eliminating all contact with the allergen, allergic reactions can be prevented. To relieve symptoms, certain medications have proven effective. To combat the immune system dysfunction that leads to allergies, desensitization is the long-term treatment.
Once the allergen has been identified, the goal is to avoid it as much as possible, which can sometimes be very restrictive! Good environmental control will help reduce exposure to the allergen.
Pollens and foods: can you link them?
Allergy symptoms are caused by a specific immune system response following exposure to an allergen. A substance that causes an allergic reaction in one person may be completely harmless in another.
It is possible to desensitize the immune system to certain allergens through subcutaneous immunotherapy treatment.
This is possible for the following allergens:
Types of Allergens
Outdoor
- Tree, weed, or grass pollen
- Mold spores
Indoor
- Dust mites
- Animals
- Mold spores
- Feathers in pillows
Food
- Nuts and peanuts
- Milk
- Eggs
What is pollen-food syndrome?
Pollen-food syndrome, also known as oral allergy syndrome, is defined as an allergic reaction in a person who experiences symptoms of allergic rhinitis or hay fever when eating fresh fruits or vegetables or nuts. Allergic symptoms are usually limited to the mouth and throat.
The explanation for this phenomenon lies in the structure of the proteins that cause allergy symptoms. Certain labile proteins in raw fruits and vegetables are very similar to those in pollen. The following associations are currently the most well-known:
Cross-reactions between pollen and food
Birch: Apple, peach, plum, pear, apricot, celery, carrot, almond, peanut, hazelnut
Ragweed: Banana, cantaloupe, watermelon, honeydew melon, cucumber, squash
Mugwort: Celery
The allergens involved in pollen-food syndrome are proteins that are sensitive to heat and cooking. This explains why a person may experience allergic symptoms when eating an apple, but may experience none if they eat a slice of apple pie.
Approximately 10% of people will experience local symptoms in the mouth and throat, and the risk of anaphylaxis is estimated at 1.7%. It is recommended that people who suspect they are affected by pollen-food syndrome undergo skin prick tests to accurately identify the foods to which they are allergic. Although the risk of anaphylaxis is minimal, it is very difficult to predict the extent of an allergic reaction. This is why it is preferable for these people to avoid eating fresh fruits or vegetables that cause them symptoms.
| S’il y a une allergie à : | Risque d’une réaction à l’un ou l’autre parmi : | % de risque |
|---|---|---|
| Bouleau | Pomme, pêche, melon miel | 55% |
| Herbe à poux | Banane, cantaloup, melon miel | 55% |
| Armoise | Céleri | 55% |
| Arachides | Pois verts, lentilles, fèves | 5% |
| Fruits de mer (ex. crevette) | Autres fruits de mer (ex. homard, crabe) | 75% |
| Lait de vache | Lait de chèvre | 92% |
| Grain entier (ex. blé) | Autres grains entiers (seigle, orge) | 20% |
| Noix (ex. noix de Grenoble) | Autres noix (ex. cachou, noisette) | 37% |
| Pêche | Pomme, cerise, poire, prune | 55% |
| Banane, kiwi, avocat | Latex | 11% |
| Latex | Banane, kiwi, avocat | 35% |
What is immunotherapy?
Allergen immunotherapy, commonly known as desensitization, is currently the only treatment that can cure allergies. Formerly based on the simple experience of doctors, this therapy is now perfectly codified by an international consensus under the aegis of the World Health Organization.
Desensitization cannot be applied to all allergies, nor to all allergic individuals. To find out if you can benefit from it, discuss it with your doctor.
You must understand that desensitization can help you, but you must participate by accepting the constraints:
- Repeated visits to your doctor
- Mandatory 30-minute wait after injection
- Duration of treatment
Two types of immunotherapy
Subcutaneous:
Injections must be given at the doctor's office.
"Perennial" treatments
Oral:
Suspensions initiated at the doctor's office and then continued at home
Oral sublingual tablet:
Allows daily treatment at home, but does not apply to all allergens. Furthermore, it only addresses one allergy per treatment.
Your specialist, once again, will be your best advisor.
The effectiveness of immunotherapy is around 80 to 85% in cases of aeroallergens (pollens, dust mites, animals, etc.)
What are the drug treatments?
Medications reduce symptoms and combat inflammation caused by allergies. The use of these medications is now well understood, particularly in cases of asthma and allergic rhinitis, and is codified by international expert consensus.
However, despite their recognized effectiveness, these medications do not treat the cause of the allergy; they do not act on the allergic person's immune system and therefore do not cure them of their allergies. Their effect only lasts as long as they are taken, with no long-term benefits.
What allergens are present according to the season?
Tree pollen (Early April to mid-June)
- Birch
- Maple
- Oak
- Poplar
- Willow
Grass pollen (Mid-June to late September)
- Bentgrass
- Orchardgrass
- Meadow fescue
- Sweet vernalgrass
- Ryegrass
- Timothy
Weed pollen (Early August to mid-October)
- Ragweed
- Amaranth
- Cocklebur
- Lamb's quarters
Refer to the pollen calendar for a quick overview of this information.
What are the recommended periods for starting desensitization?
When it's time to start desensitization, it's recommended to wait until the current pollen season is over. For example, desensitization to tree pollen can begin in mid-June. It's possible to initiate desensitization until the end of January, three months before the start of the new tree pollen season. The same recommendation applies to grass pollen desensitization: it can begin in October, and treatment can be initiated until the end of March. For weed pollen, desensitization can begin in mid-October, and treatment can be initiated until the end of May, preceding the upcoming pollen season.
Consult the pollen calendar to quickly visualize this information.
Are desensitization treatments dangerous?
In the case of immunotherapy, we are not talking about a vaccine (a vaccine being an injection of an infectious organism, bacterium or virus, in a harmless form, with the aim of preventing or stopping the serious disease it would have caused), we are talking about treatment here.
In immunotherapy, we are talking more about treatment. The injected allergens are naturally harmless, and if the protocol for administering these treatments is followed scrupulously, the risk of a severe systemic reaction is low.
- For your safety, always follow these instructions:
- Wait 30 minutes after injection at the doctor's office
- Measure and note the induration at the injection site
- Do not increase the dose if the measured induration exceeds 5 cm
- Do not increase doses during the policlinic season
Can doses be spaced out or skipped?
No. This would oblige the doctor to reduce the doses, which would slow down the progression of the treatment and thus delay the results.
If such a situation occurs, always notify your specialist doctor so that they can adequately adjust the new doses.
Please do not hesitate to contact us for any further questions or additional information.