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Июл
16,
2020

Allergies : prevention and treatments

Июл 16, 2020

Worldwide, allergies are on the rise at an alarming rate. The World Allergy Organization (WAO) warn that “allergic diseases constitute a significant cause of morbidity worldwide and a considerable burden on the health and medical systems of both developed and emerging economies”.[1]

With 40 to 50 percent of schoolchildren[2] worldwide sensitized to one or more allergens, preventing allergies in the future is likely to have a huge impact on global health.

During the summer season, we’re facing a host of allergens that can trigger respiratory disorders. «Summer allergies can cause severe symptoms for some sufferers, and can be just as bad as the spring and fall seasons,» said allergist Michael Foggs, MD, president of the American College of Allergy, Asthma and Immunology (ACAAI).[3]

 

Understanding allergies

The term “allergy” was coined by Clemens von Pirquet in 1906 to call attention to the unusual propensity of some individuals to develop signs and symptoms of reactivity, or hypersensitivity reactions’, when exposed to certain substances.[4]

Allergies are a very common overreaction of the immune system to usually harmless substances. How do our bodies mistake otherwise harmless substances for potential dangers and cause the unpleasant, and sometimes even fatal, symptoms of allergy?

The mucosal immune system of the respiratory tract is specialized to continuously monitor the external environment and to protect against invading pathogens, while maintaining tolerance to innocuous inhaled particles. Allergies result from a loss of tolerance against harmless antigens characterized by formation of allergen-specific Th2 cells and Immunoglobulin E. Tolerance is often described as a balance between harmful Th2 cells and various types of protective “regulatory” T cells.

Understanding the basis of tolerance is essential for the rational design of novel and more efficient immunotherapies. [5]

Allergies may start in patient with genetic predisposition and exposition to allergens. They are the consequence of an immune system dysfunction: it unwittingly fights against substances that are not normally deemed harmful, allergens. Pollens, mites, pollen allergens, animal protein, atmospheric molds are susceptible to enhance allergic reactions.

Allergic reactions may cause inflammation that, in turn, can be exacerbated by respiratory infections caused by microorganisms.

The number of people developing allergies has considerably increased over the past few decades. Allergies affect 25% to 30% of the world population.

 

What is Allergic Rhinitis?

Allergic rhinitis is known to be one of the most common chronic diseases in the industrialized world. It is an allergic reaction to airborne allergens. These allergens can be seasonal like seasonal grass or pollen or year-round like dust and animal dander.

Allergic rhinitis is widely known as “hay fever,” especially when caused by seasonal allergens. Hay fever shares many of the same symptoms as a common cold, but is not caused by a virus or bacteria. It is in fact caused by the immune system reacting to allergens breathed into the body.

Allergic rhinitis takes two different forms:

  1. Seasonal allergic rhinitis: Symptoms can occur in spring, summer and early fall. They are usually caused by allergic sensitivity to pollens from grass, trees and weeds.
  2. Perennial allergic rhinitis: People with perennial allergic rhinitis experience symptoms year-round. It can be caused by dust mites, pet hair or dander, cockroaches or mold.

.Allergic rhinitis (AR) is an extremely common health problem affecting between 10–25% of the world’s population. Patients with AR suffer from both nasal symptoms (congestion, rhinorrhea, itching, and sneezing) and ocular symptoms (itching, redness, and tearing). The negative impact on sleep quality and quantity, and consequently on various aspects of the patient’s life, is an under-recognized and under-treated component of AR morbidity.[6]

Respiratory allergies are often diagnosed in serval member of the same family: mother, father, sisters, and brothers.  7 times out of 10 someone with both parents being allergic will also develop an allergy.[7]

 

Prevention and treatments of allergic reactions

An allergy management plan is key to preventing allergic reactions so working with a doctor to create one is essential. A good allergy management plan is based on medical history, the results of allergy tests and how severe symptoms are. It can include three treatment types: avoiding allergens, medicine options and/or immunotherapy (allergens given as a shot or placed under the tongue).  Avoiding allergens however is not always easy.

Allergy medicines currently available include nasal corticosteroids (nose sprays), antihistamines, mast cell stabilizers that keep your body from releasing histamine, decongestants, corticosteroid creams or oral corticosteroids and epinephrine that comes in a pre-measured and self-injectable device. It is the most important medicine to give during a life-threatening anaphylaxis (severe allergic reaction). It treats life-threatening allergic reactions to food, stinging insects, latex and drugs/medicines.

While common allergy medications often control symptoms, if you stop taking the medications, your allergy symptoms return shortly afterward. Immunotherapy can potentially lead to lasting remission of allergy symptoms, and it may play a preventive role in terms of development of asthma and new allergies.

Polyvalent bacterial lysates (PBL) have been used for many years to prevent respiratory tract infections in children and adults. Another study conducted in 2019 demonstrated that « PMBL was able to significantly improve Seasonal allergic rhinitis (SAR) symptoms in children. »[8]

In another recent article, the administration of bacterial lysates as another immunomodulatory strategy, particularly appealing in pediatric asthma, is positively reviewed, and has proven to be efficient in preventing respiratory tract infections in adult and pediatric patients with chronic bronchitis and/or history of recurrent chronic infections.[9]

 

REFERENCES :

[1] The importance of allergic disease in public health: an iCAALL statement,

MarioSánchez-Borges, Bryan L.Martin, Antonella M.Muraro, Robert A.Wood, Ioana O.Agache, Ignacio J.Ansotegui, Thomas B.Casale, Thomas A.Fleisher, Peter W.Hellings, Nikolaos G.Papadopoulos, David B.Peden, James L.Sublett, Stephen A.Tilles, LannyRosenwasse, World Allergy Organization Journal 2018,

https://doi.org/10.1186/s40413-018-0187-2

[2] https://www.aaaai.org/about-aaaai/newsroom/allergy-statistics

[3] https://acaai.org/news/ugly-truth-about-summer-allergies

[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3573758/

[5] Antigen-specific regulatory T-cell responses against aeroantigens and their role in allergy, Petra Bacher & Alexander Scheffold , Mucosal Immunology 11, 1537–1550 (2018), https://doi.org/10.1038/s41385-018-0038-z

[6] Storms, W. Allergic rhinitis-induced nasal congestion: its impact on sleep quality. Prim Care Respir J 17, 18–12 (2008). https://doi.org/10.3132/pcrj.2008.00001

[7] https://www.inserm.fr/information-en-sante/dossiers-information/rhinite-allergique

[8] Janeczek KP, Emeryk A, Rapiejko P. Effect of polyvalent bacterial lysate on the clinical course of pollen allergic rhinitis in children. Postepy Dermatol Alergol. 2019;36(4):504-505. doi:10.5114/ada.2019.87457

[9]  L. Stéphanie, D. Antoine, L. Rouzic Olivier, E. Ilka, D. Rodrigue, P. Muriel, G.

Philippe, Childhood asthma heterogeneity at the era of precision medicine: Modulating the immune response or the microbiota for the management of asthma attack, Biochemical Pharmacology (2020), doi: https://doi.org/10.1016/j.bcp.2020.114046