Allergies
Definition
Allergy is caused by a person's reaction to environmental molecules or particles called "allergens."
They are present all around us, but do not affect everyone in the same way. They are found in dust mites, pollen, insects, foods, medications, etc. The immune system causes inflammation leading to various symptoms, such as:
Asthma
Rhinitis
Urticaria
Eczema
Swellings
Etc.
They can affect different parts of the body such as the nose, eyes, lungs, skin, etc. Although the allergy is often not serious, there are certain fatal forms which must then be treated urgently.
The main allergies
Allergic Rhinitis and Conjunctivitis
Allergic rhinitis is a chronic rhinitis, defined by the WHO (World Health Organization) as an inflammation of the nasal mucosa induced by allergens, which can be subdivided, according to the mode of occurrence, into: intermittent, persistent and occupational rhinitis.
Rhinitis is clinically characterized by at least two of the following symptoms: nasal obstruction, rhinorrhea, sneezing, nasal pruritus and/or posterior nasal discharge. Rhinitis is frequently associated with ocular (conjunctivitis) or bronchial (asthma) symptoms.
The etiological diagnosis of intermittent pollen rhinitis is often easy, based essentially on clinical history, nasal examination and immediate allergy skin tests. The dosage of source-specific and/or molecular unit IgE is useful in cases of polysensitization.
The etiological diagnosis of persistent rhinitis is more complex and requires looking not only for allergenic sensitizations, but also for associated irritant factors. These factors are important to know because they are also aggravating factors, which should be identified and managed for each patient. These include viral infections, pollution, and associated sinus disorders.
A complete allergy assessment is therefore necessary to establish the etiological diagnosis and facilitate therapeutic management. It is based on a precise interview and some additional examinations.
Apart from allergic rhinitis we distinguish:
Pregnancy and/or hormonal rhinitis
Eosinophilic rhinitis
Occupational rhinitis
Rhinitis drug
The management of rhinitis is gradual, taking into account the severity and the etiological mechanism:
Mild intermittent or persistent rhinitis:
- H1 antihistamines, oral or local;
- Washing the nose with salt water.
Moderate to severe intermittent rhinitis:
- H1 antihistamines, oral or local;
- Nasal corticosteroids;
- Allergen immunotherapy.
Intramuscular injections and local infiltrations of corticosteroids are not indicated (potentially severe general and local side effects).
Wasp or bee sting allergy
Sensitization to hymenoptera venoms is common. Several studies report the presence of specific serum IgE and positive skin tests in 10 to 40% of the general population, without all of these subjects necessarily having a systemic allergic reaction to a sting (Sturm, 2008).
The frequency of occurrence of extensive local reactions varies from 2 to 26% in the general population.
The frequency of systemic reactions occurring after a hymenoptera sting has been evaluated in numerous surveys; they report a frequency of 0.3 to 7.5% in the general population (Bilo, 2009), in children and 35-50% of patients who have already had a systemic reaction before and not treated with allergen immunotherapy.
In beekeepers, general reactions could reach 15 to 43% of these highly exposed subjects (Müller, 1990).
Systemic reactions occur in 22-49% of adults and 6-9% of children with mast cell activation syndrome. They represent 1-7.9% of patients allergic to hymenoptera venoms (Bonadona, 2016).
Immediate systemic reactions are classified into 4 stages of severity according to the Ring and Messmer or Müller classifications:
Stages I (or mild) and II (or moderate)
Represents moderate general reactions without associated cardio-respiratory manifestations: urticaria, edema with or without subjective feelings of malaise, chest tightness, anxiety, etc.
Stages III and IV (or severe)
They are the most severe, they are life-threatening and require immediate treatment with adrenaline.
At stage IV
The cardiovascular collapse of anaphylactic shock is in the foreground, urticaria often only appears during the repair phase; it indicates the allergic origin of the accident.
Possibly an antihistamine;
Possibly a fast-acting inhaled β2 mimetic.
Possibly an oral or injectable glucocorticoid, the use of which is not urgent and only in cases of upper airway involvement;
Self-injectable adrenaline, mainly JEXT® or EpiPen®, the use of which must be meticulously explained and written in a separate document;
In case of an initial local, extensive or systemic reaction
the prescription of an emergency kit will be systematic; it includes:
For severe reactions with a proven allergic mechanism, the treatment of choice is desensitization (subcutaneous allergen immunotherapy).
Desensitization usually results in healing, including the absence of a severe reaction during a subsequent sting.
The desensitization protocol is based on the repetitive injection of an increasing amount of venom leading to the induction of tolerance.
The diagnosis is based on the precise anamnesis and on the performance of specific IgE biological tests as well as the dosage of mast cell tryptase.
The main purpose of mast cell tryptase assay is to identify patients with Mast Cell Activation Syndrome - a major risk factor in severe systemic reactions.
Anaphylaxis
Anaphylaxis is a rapid, generalized, often unpredictable allergic reaction that can lead to death within minutes if an injection of epinephrine (JEXT or EPIPEN) is not given.
Symptoms of anaphylaxis can affect multiple organs, including the skin, respiratory, gastrointestinal, and cardiovascular systems upon contact with an allergen.
The situation is URGENT and requires immediate use of the epinephrine auto-injector.
Diagnosis in allergology
Pulmonary function tests (PFT)
These are tests that measure the lungs' ability to breathe in and out of air, as well as how efficiently they transfer oxygen into the blood.
The native food prick test
It is a skin test that detects food allergies using fresh foods that are applied to the skin.
Reading takes 15-30 minutes.
Specific IgE
It is a blood test that detects allergies by measuring the amount of allergen-specific immunoglobulin E (IgE) in the blood.
The prick test
It is a skin test that detects allergies by introducing a small amount of allergenic extract into the skin.
Reading takes 15-30 minutes.
L'IgE Microarray
(ISAC)
It is a blood test that detects allergies by using microarray technology to measure the amount of specific IgE to several allergens at the same time (approximately 120 allergens analyzed concomitantly).
The Oral Provocation Test
This is a test that detects food or drug allergies by observing the immune system's response to a specific drug. The oral challenge test involves giving a food to which the person is suspected of being allergic by mouth. Small amounts of the food are started and gradually increased during the test.
Your treatment proposals
Antihistamines
These are medications used to treat allergies by blocking the action of histamine, a chemical released by the body in response to an allergy.
Nasal corticosteroids
These are medications used to treat allergies by reducing inflammation in the nasal passages. They can help relieve symptoms such as sneezing, itching, and stuffy nose.
Aerosol therapy
It is the administration of medications by inhalation. This method allows the medications to act directly on the airways, which can be useful in the treatment of asthma and other respiratory diseases.
Anti-leukotrienes
These are drugs used to treat asthma by blocking the action of leukotrienes, chemicals released by the body that can cause inflammation in the airways.
Monoclonal antibodies
These are medications used to treat allergies by specifically targeting the cells responsible for the allergic reaction. They can help reduce symptoms and prevent future allergic reactions.