Allergic rhinitis

Allergic rhinitis, or hay fever, is the most common manifestation of respiratory allergy. It is caused by an abnormal and excessive immune response when the organism encounters a foreign substance or a substance to which it has become sensitive. Allergic rhinitis is associated with dysbiosis of the ENT microbiota and gut microbiota. 

Created 13 October 2020
Updated 14 May 2024

About this article

Created 13 October 2020
Updated 14 May 2024

400 million sufferers 

Tickling sensations, sneezing fits, watery eyes, itching, a blocked or runny nose... Although very common, allergic rhinitis has a real impact on sufferers’ quality of life.  Approximately 400 million people suffer with this respiratory allergy1. 
Allergic rhinitis is described as seasonal (known as “hay fever”) when it is linked to tree, grass, or herbaceous pollens. It is described as perennial when it is due to allergens that are present all year round, such as dust mites, molds, or animal hair (cats and dogs) 2

40% Allergic rhinitis is thought to affect up to 40% of the global population with a high prevalence.

The symptoms of allergic rhinitis 

Allergic rhinitis has very characteristic symptoms, usually a combination of 3

  • Pruritus (itching, irritation) 
  • Anosmia (loss of smell) 
  • Rhinorrhea (runny nose) 
  • Repeated sneezing 
  • Nasal obstruction (blocked nose) 

In seasonal allergic rhinitis and perennial allergic rhinitis, these symptoms are exacerbated. 

Modified microbiota 

Imbalances in the gut microbiota and in the ENT microbiota (ear-nose-throat microbiota), also known as “dysbiosis”, have been demonstrated in cases of allergic rhinitis. This dysbiosis is characterized by a low diversity of the gut microbiota 4,5, and a composition of the ENT microbiota (ear-nose-throat microbiota) that differs from that of healthy individuals 6-8. Finally, all the factors that can impact the gut microbiota (antibiotics, diet, etc.) during the perinatal period may have long-term effects on allergy susceptibility 9

Treatments for allergic rhinitis 

The treatment of allergic rhinitis is based on 3 approaches: avoidance of allergens, medication and desensitization. There are also symptomatic treatments to improve comfort 10. Finally, the approach of correcting (sidenote: Dysbiosis Generally defined as an alteration in the composition and function of the microbiota caused by a combination of environmental and individual-specific factors. Levy M, Kolodziejczyk AA, Thaiss CA, et al. Dysbiosis and the immune system. Nat Rev Immunol. 2017;17(4):219-232.   ) and rebalancing the microbiota with probiotics is being studied, with promising results. These probiotics seem to be effective in improving the symptoms of allergic rhinitis and enhancing patients’ quality of life 11


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3 Brożek JL, Bousquet J, Agache I, et al. Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines-2016 revision. J Allergy Clin Immunol. 2017 Oct;140(4):950-958.  
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5 Coker MO, Juliette C. Madan JC. Chapter 3 - The microbiome and immune system development, The Developing Microbiome. Academic Press. 2020. p 43-66. 
6 Lyu J, Kou F, Men X, Liu Y, Tang L, Wen S. The Changes in Bacterial Microbiome Associated with Immune Disorder in Allergic Respiratory Disease. Microorganisms. 2022 Oct 19;10(10):2066.  
7 Kang HM, Kang JH. Effects of nasopharyngeal microbiota in respiratory infections and allergies. Clin Exp Pediatr. 2021 Apr 15. 
8 Zhou Y, Jackson D, Bacharier LB, et al. The upper-airway microbiota and loss of asthma control among asthmatic children. Nat Commun. 2019 Dec 16;10(1):5714. 
Kalbermatter C, Fernandez Trigo N, Christensen S, et al. Maternal Microbiota, Early Life Colonization and Breast Milk Drive Immune Development in the Newborn. Front Immunol. 2021 May 13;12:683022. 
10 Richard D deShazo, Stephen F Kemp. Patient education: Allergic rhinitis (Beyond the Basics). UpToDate. 2021 
11 Luo C, Peng S, Li M et al. The Efficacy and Safety of Probiotics for Allergic Rhinitis: A Systematic Review and Meta-Analysis. Front Immunol. 2022 May 19;13:848279.