[2] Allergic rhinitis is typically triggered by environmental allergens such as pollen, pet hair, dust, or mold.

[2] The underlying mechanism involves IgE antibodies that attach to an allergen, and subsequently result in the release of inflammatory chemicals such as histamine from mast cells.

[2] It causes mucous membranes in the nose, eyes and throat to become inflamed and itchy as they work to eject the allergen.

[3] Several different types of medications reduce allergic symptoms, including nasal steroids, intranasal antihistamines such as olopatadine or azelastine, 2nd generation oral antihistamines such as loratadine, desloratadine, cetirizine, or fexofenadine; the mast cell stabilizer cromolyn sodium, and leukotriene receptor antagonists such as montelukast.

[citation needed] Pollen is often considered as a cause of allergic rhinitis, hence called hay fever (See sub-section below).

[citation needed] Predisposing factors to allergic rhinitis include eczema (atopic dermatitis) and asthma.

[25] Additionally, environmental exposures such as air pollution and maternal tobacco smoking can increase an individual's chances of developing allergies.

Examples of plants commonly responsible for hay fever include: Allergic rhinitis may also be caused by allergy to Balsam of Peru, which is in various fragrances and other products.

[27][28][29] The causes and pathogenesis of allergic rhinitis are hypothesized to be affected by both genetic and environmental factors, with many recent studies focusing on specific loci that could be potential therapeutic targets for the disease.

On the other hand, CTLA-4 is an immune-checkpoint protein that helps mediate and control the body's immune response to prevent overactivation.

Both SNPs most likely affect the associated protein's shape and function, causing the body to exhibit an overactive immune response to the posed allergen.

[citation needed] Finally, epigenetic alterations and associations are of particular interest to the study and ultimate treatment of allergic rhinitis.

Specifically, microRNAs (miRNA) are hypothesized to be imperative to the pathogenesis of allergic rhinitis due to the post-transcriptional regulation and repression of translation in their mRNA complement.

Both miRNAs and their common carrier vessel exosomes have been found to play a role in the body's immune and inflammatory responses to allergens.

miRNAs are housed and packaged inside of exosomes until they are ready to be released into the section of the cell that they are coded to reside and act.

There are many miRNAs that have been deemed potential therapeutic targets for the treatment of allergic rhinitis by many different researchers, with the most widely studied being miR-133, miR-155, miR-205, miR-498, and let-7e.

[31][36][37][38] The pathophysiology of allergic rhinitis involves Th2 Helper T cell and IgE mediated inflammation with overactive function of the adaptive and innate immune systems.

[11] Disruption of the nasal mucosal epithelial barrier may also release alarmins (a type of damage associated molecular pattern (DAMP) molecule) such as thymic stromal lymphopoietin, IL-25 and IL-33 which activate group 2 innate lymphoid cells (ILC2) which then also releases inflammatory cytokines leading to activation of immune cells.

So skin-prick and blood tests for allergy are negative, but there are IgE antibodies produced in the nose that react to a specific allergen.

[42] As of 2014, local allergenic rhinitis had mostly been investigated in Europe; in the United States, the nasal provocation testing necessary to diagnose the condition was not widely available.

[47] Specific anti-allergy zippered covers on household items like pillows and mattresses have also proven to be effective in preventing dust mite allergies.

[39] Studies have shown that growing up on a farm and having many older siblings can decrease an individual's risk for developing allergic rhinitis.

There is not enough evidence of antihistamine efficacy as an add-on therapy with nasal steroids in the management of intermittent or persistent allergic rhinitis in children, so its adverse effects and additional costs must be considered.

In the United States, oral decongestants containing pseudoephedrine must be purchased behind the pharmacy counter in an effort to prevent the manufacturing of methamphetamine.

[52] Desloratadine/pseudoephedrine can also be used for this condition[citation needed] Intranasal corticosteroids are used to control symptoms associated with sneezing, rhinorrhea, itching, and nasal congestion.

[55] Other measures that may be used second line include: decongestants, cromolyn, leukotriene receptor antagonists, and nonpharmacologic therapies such as nasal irrigation.

[citation needed] For nocturnal symptoms, intranasal corticosteroids can be combined with nightly oxymetazoline, an adrenergic alpha-agonist, or an antihistamine nasal spray without risk of rhinitis medicamentosa.

[56] Nasal saline irrigation (a practice where salt water is poured into the nostrils), may have benefits in both adults and children in relieving the symptoms of allergic rhinitis and it is unlikely to be associated with adverse effects.

[61][62] While some evidence shows that acupuncture is effective for rhinitis, specifically targeting the sphenopalatine ganglion acupoint, these trials are still limited.

[63] Overall, the quality of evidence for complementary-alternative medicine is not strong enough to be recommended by the American Academy of Allergy, Asthma and Immunology.