Allergic rhinitis affects the quality of life of millions of people around the world. Annually, about 3 million people die from exposure to poor air quality. In addition, allergic rhinitis and air pollution interact.
What is allergic rhinitis?
Allergic rhinitis is an allergic disease of the nasal mucosa of type I, characterized by paroxysmal, repeated sneezing reflex, runny nose and nasal congestion and congestion. In addition to the symptoms listed, patients with allergic rhinitis may also suffer from allergic conjunctivitis, a fatiguing cough, eustachian tube dysfunction and chronic sinusitis. After an accurate diagnosis, allergic rhinitis can be treated in a variety of ways, with intranasal glucocorticoids being the first-line medications.
The allergic response is divided into early and late phase reactions. In the early phase, allergic rhinitis is an IgE response to exposure to inhaled allergens that cause inflammation caused by type 2 helper cells. The initial response occurs within five to 15 minutes of exposure to the antigen, causing degranulation of the host mast cells. This leads to the release of various preformed and newly synthesized mediators, including histamine, which is one of the major mediators of allergic rhinitis. Histamine induces sneezing through the trigeminal nerve and also plays a role in nasal discharge by stimulating the mucous glands. Other immune mediators such as leukotrienes and prostaglandins are also involved as they act on blood vessels, causing nasal congestion. Four to six hours after the initial response, there is an influx of cytokines such as the interleukins IL-4 and IL-13 from mast cells, signifying the development of a late phase response. There is evidence to suggest a genetic component of allergic rhinitis, but high-quality research is generally lacking.
Treatment of allergic rhinitis
The aim of treatment is to alleviate symptoms so that you can function freely in everyday life. Avoidance of triggers (keeping track of the pollen calendar and limiting outdoor exposure when allergen levels are high) is encouraged. You also have to close the windows in the apartment. After a long stay outside, change and take a shower as pollen is deposited on clothes, skin and hair. People allergic to house dust mites should remove carpets, upholstered furniture and other items that are dust stores. In addition, it is important to wash the bedding frequently at temperatures above 60 degrees Celsius. Cleaning should be done using a vacuum cleaner with a high-efficiency HEPA filter. Patient adherence to the treatment regimen is essential to relieve symptoms.
Pharmacological methods include antihistamines, nasal steroids, leukotriene receptor antagonists (LTRAs), and immunotherapy.
Nasal corticosteroids may be used alone or in combination with oral antihistamines in patients with mild, moderate or severe symptoms. Studies have shown that nasal corticosteroids are superior to antihistamines in effectively reducing rhinitis and improving mucosal pathology. Therefore, the topical nasal steroid should be the first line treatment for allergic rhinitis. Commonly available nasal sprays include:
fluticasone furoate (Avamys),
mometasone furoate (Eztom, Metmin, Momester, Pronasal),
fluticasone propionate (Fanipos, Flixonase),
budesonide (Tafen Nasal)
Correct administration of the nasal spray is essential to obtain an optimal clinical response and to avoid side effects. Therefore, patients should always be advised on the correct use of the sprays. They should be used regularly as the healing effects may take many days to develop. The tip of the spray bottle should be placed directly in the nose and pointing sideways towards the eye on the same side to minimize contact of the product with the nasal septum. The most common side effect reported is nasal irritation followed by epistaxis. This can be prevented by spraying a spray from the nasal septum. Oral and injectable steroids have been shown to reduce the symptoms of allergic rhinitis but are not recommended for routine use due to their significant systemic side effect profile.
First-generation antihistamines include diphenhydramine, chlorpheniramine, and hydroxyzine, while fexofenadine, loratadine, desloratadine, and cetirizine are examples of second-generation antihistamines. Both first- and second-generation antihistamines are effective in relieving the symptoms of AR. Still, generation 1 antihistamines may have a calming effect due to their ability to cross the blood-brain barrier. These agents also act on muscarinic receptors, causing side effects such as dry mouth, urinary retention, constipation and / or tachycardia. Second-generation antihistamines are more selective for H1 receptors and therefore have a lower sedative effect, and have a longer half-life (12 to 24 hours) than first-generation drugs. Fexofenadine is not sedative, but loratadine and desloratadine may induce sleep at higher doses. Cetirizine has the greatest sedative potential of any second-generation antihistamine. There is no one substance recommended more than the others, as they all demonstrated similar efficacy and safety profiles in terms of symptom relief.
Nasal antihistamines such as azelastine are fast acting and more effective than oral antihistamines in relieving symptoms of rhinitis. They are recommended as first-line or second-line therapies for AR and may be used in conjunction with topical corticosteroid nasal sprays.
The leukotriene receptor (LTRA) antagonists montelukast and zafirlukast may have a beneficial effect in patients with allergic rhinitis, but are not as effective as nasal corticosteroids. They are often used in combination therapy with other drugs for severe or resistant symptoms. Allergen immunotherapy should be considered in patients who are treated with measures to eliminate exposure to triggers and when combination drug therapy is ineffective, allergen immunotherapy should be considered. Commonly used therapies are subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT). Weekly incremental doses are given for 6 to 8 months, followed by maintenance doses for 3 to 5 years. Usually, patients experience a long-term protective effect and the therapy can be discontinued.
Oral decongestants such as pseudoephedrine are useful in relieving symptoms but are not recommended for long-term daily use due to their side effect profile. Nasal decongestants such as xylometazoline are alpha agonists that cause blood vessels to contract. Long-term use of nasal decongestants poses a risk of recurrence of nasal congestion (rhinitis) and should therefore not be used for more than a week. Disodium cromoglycate is effective in reducing sneezing reflex, runny nose and itching, so it is a good alternative in managing symptoms. Surgical treatment is reserved for patients with nasal polyps, an enlarged inferior turbinate causing difficult-to-remove nasal obstruction, or treatment-resistant chronic sinus disease. Budesonide is the only FDA-approved agent for pregnant women who develop symptoms of allergic rhinitis. Omalizumab, a monoclonal antibody, is beneficial in AR patients, although cost of treatment is a limiting factor in its use. Saline solution can be a useful alternative in combination with other nasal treatments.
Allergic rhinitis is most often diagnosed and treated by GPs. However, patients who fail traditional AR treatments qualify for referral to a specialist such as an allergist or ENT specialist with an allergy focus. If you have symptoms that may indicate this disease, consult a doctor.
Kimihiro Okubo, Japanese guidelines for allergic rhinitis 2020,
Akhouri, S. A. House, Allergic Rhinitis
Eli O. Meltzer, MDAriel Teper, MD, Melvyn Danzig, PhD, Intranasal glucocorticosteroids for the treatment of acute rhinosinusitis