Allergic rhinitis: spring is worth remembering
Introduction
Allergic rhinitis (AR) is clinically defined as allergen-induced and immunoglobulin E-dependent chronic inflammation of the nasal mucosa (1).
According to the World Allergy Organization, AR affects 10-30% of adults and even 40% of children. In Europe, the prevalence of this disease ranges from 4% to 32%. AR is not limited to the nose alone. People with AR often have symptoms of other allergic diseases such as conjunctivitis, atopic dermatitis, and bronchial asthma. More than 40% of AR patients are diagnosed with asthma, and more than 80% of those with asthma also have AR (2). 70% of AR patients with pollen-induced AR also suffer from conjunctivitis (3). AR is associated with other conditions such as sinusitis, nasal polyposis, frequent upper respiratory tract infections, and serous otitis media (2). It has been found that AR is one of the top 10 reasons why patients consult primary care physicians. It is usually not a severe condition, but it significantly affects a person's social life, learning ability, and work productivity. Additionally, there are considerable costs associated with rhinitis (2, 4).
Risk factors for the development of AR include a family history of atopic diseases, elevated total immunoglobulin E levels in the blood by the age of 6, positive skin allergy tests showing a first type allergic reaction (skin prick tests), and a higher socioeconomic class (2).
Classification of AR
According to modern classification, AR is divided into episodic and persistent based on the duration of the disease. When symptoms occur less than 4 days a week or less than 4 weeks, AR is considered episodic, while when symptoms persist for more than 4 days a week and more than 4 weeks, it is called persistent.
Based on the severity of symptoms and their impact on quality of life, AR is classified as mild or moderate to severe. Moderate to severe AR is characterized by 1-3 or all 4 indicators of impaired quality of life: abnormal sleep, disrupted daily, sports and leisure activities, work or school problems, bothersome symptoms. With mild AR, there is no impact on quality of life (1).
Pathogenesis of AR
Allergic nasal inflammation is an accumulation of T lymphocytes, mast cells, and eosinophils in the nasal mucosa. It develops in three phases:
1. Sensitization.
2. Early-phase reaction.
3. Late-phase reaction.
Sensitization occurs during the initial contact with the allergen in the nasal mucosa. Specific IgE class antibodies are produced against the allergen, which bind to mast cells.
Upon subsequent contact with the allergen, interacting with IgE on mast cells causes their degranulation and release of primary mediators such as histamine. Acute rhinitis symptoms appear: sneezing, itching, watery discharge, and less nasal congestion.
The late phase involves an increased influx of inflammatory cells, production, and secretion of secondary mediators. Chronic rhinitis symptoms manifest: nasal congestion, loss of smell, nasal hyperreactivity, i.e., increased nonspecific nasal sensitivity (4).
Frequently occurring eye symptoms in patients with AR may occur due to the so-called nasal and ocular reflex, which is determined by specifically located parasympathetic fibers, and, of course, due to local allergic inflammation occurring in the ocular mucosa (3).
For episodic AR, often triggered by pollen allergens, both phases are characteristic. For perennial AR, interaction of allergens with ongoing allergic inflammation is characteristic. Not always for patients with perennial AR, contact with the allergen is constant, but a persistent minimal inflammation continues even without disease symptoms. Therefore, it is important to reduce this inflammation, not just the symptoms of the disease (1).
The early phase is effectively blocked by antihistamines, mast cell membrane stabilizers, reducing acute rhinitis symptoms associated with this phase. The late phase is effectively blocked by glucocorticosteroids, reducing chronic rhinitis symptoms associated with this phase (1).
Etiology
AR is most commonly caused by inhaled allergens. The main indoor allergens are house dust mites, domestic animal epidermis, hair, bird feathers, cockroaches, microscopic fungi. The main outdoor allergens are grasses, weeds, tree pollens, seasonal microscopic fungal spores. Even 70–90% of pollen-allergic individuals are sensitive to plant food - vegetables, various greens, fruits, nuts (cross-reactions). The periods of most intense flowering and highest pollen concentrations in the air in Lithuania are: trees – May, grasses – June, weeds – August (1).
Classical AR symptoms include:
•nasal discharge – rhinorrhea (anterior and/or posterior - clear, colorless discharge), sniffing;
•nasal itching – nose rubbing, "allergic salute," transverse nasal crease, the patient may complain of mouth or throat itching;
•sneezing;
•nasal mucosal swelling (obstruction) – "blockage," mouth breathing, snoring, sleep apnea, dark circles under the eyes (correlates with the chronic course and severity of the disease), nasal voice tone, impaired smell (1, 5).
Atypical AR symptoms, especially in children:
•ear pain, decreased hearing due to Eustachian tube dysfunction, chronic exudative otitis media;
•cough – often misdiagnosed as asthma;
•poorly controlled asthma – often due to concomitant undiagnosed, hence untreated rhinitis;
•sleep disturbances – fatigue, worsened learning, irritability;
•prolonged and frequent respiratory tract infections;
•oral allergy syndrome – especially when pollen-induced AR is present;
•rhinosinusitis – headache, facial pain, bad breath, cough, decreased smell, purulent or copious mucous discharge (5).
AR occurring during plant flowering, caused by tree, grass, weed pollens, is called hay fever or pollinosis. It is characterized by more acute rhinitis symptoms ("runny nose"),Conjunctivitis. From AR, caused by house dust mites, characteristic symptoms of chronic rhinitis ("dry nose") are present (1).
Diagnosis
AR is diagnosed based on history (less than 2 classic AR symptoms, related diseases, family allergy history), nasal examination with a rhinoscope, and diagnostic tests.
Allergic skin tests and/or determination of allergen-specific IgE antibodies in the blood serum are performed to confirm the origin of AR, and provocation tests, although not standardized yet. To differentiate AR from non-AR, a cytological examination of nasal secretions to detect eosinophilia is useful. The eosinophil count in the blood rarely increases in isolated AR. Nasal endoscopy is informative for visualizing polyps, acoustic rhinometry can show narrowing of the nasal cavity, and sinus X-ray or computed tomography is useful for diagnosing rhinosinusitis (1, 5).
Treatment
AR treatment consists of 3 main methods:
• allergen avoidance and removal;
• pharmacotherapy;
• specific immunotherapy.
Stepwise drug therapy is prescribed. First-line medications for mild intermittent AR are oral or nasal H1 antihistamines. Oral antihistamines are often better tolerated than nasal sprays. Decongestants are recommended for a short course only in cases of severe nasal obstruction to restore nasal patency before using other nasal sprays. Leukotriene receptor antagonists (LRA) may be prescribed for asthma symptoms.
For moderate to severe intermittent and mild persistent AR, treatment should also start with oral or nasal H1 antihistamines. Decongestants may be added for a short course if needed. If the effect is insufficient, nasal corticosteroids, LRA, or cromones may be prescribed. Nasal corticosteroids effectively reduce all rhinitis symptoms, alleviate eye symptoms, but their maximum effect is not immediate, usually seen after a few days.
For moderate to severe persistent AR, first-line treatment includes nasal corticosteroids. For acute rhinitis symptoms (sneezing, itching), oral H1 antihistamines may be added. Treatment can be combined with LRA. If there is no improvement, the dose of corticosteroids should be increased. In cases of significant nasal obstruction, in addition to decongestants, a short course of oral corticosteroids may be prescribed.
To reduce eye symptoms, it is advisable to use oral or eye drops of H1 antihistamines, and artificial tears.
It is recommended not to forget about rinsing the nasal mucosa with a physiological or hypertonic saline solution, especially after contact with an allergen. They are recommended for rhinitis of any severity and etiology. It has been proven that rinsing the nasal mucosa in children reduces the need for nasal corticosteroid sprays (5, 6).
As we can see, oral antihistamines play an important role in the treatment of AR and the often associated conjunctivitis. Recommendations indicate the use of second-generation oral H1 antihistamines, as they do not cause or almost do not cause unwanted sedative, anticholinergic, cardiotoxic, or tachyphylactic effects, unlike first-generation antihistamines (5, 6).
One of the newest second-generation H1 antihistamines is bilastine (Opexa®). Its effectiveness in reducing AR symptoms and safety has been proven in clinical trials. It has also been shown that this drug effectively reduces the symptoms of concomitant conjunctivitis. Several studies confirming this are reviewed in an article by J. Bartra and colleagues (3).
In a randomized, placebo-controlled trial involving 721 patients with seasonal allergic rhinoconjunctivitis, a dose of 20 mg/day bilastine and a dose of 5 mg/day desloratadine significantly reduced eye symptoms (itching, tearing, redness) after 7 and 14 days compared to placebo. In another similar trial with 683 patients suffering from seasonal allergic rhinoconjunctivitis, a dose of 20 mg/day bilastine and a dose of 10 mg/day cetirizine also significantly reduced eye symptoms compared to placebo. In another study, the effects of bilastine, cetirizine, and fexofenadine on eye symptoms after a provocation test with pollen were investigated. The study included 75 patients with pollen-induced rhinoconjunctivitis. One hour after provocation, all three drugs significantly reduced eye symptoms. After 26 hours, the effects of bilastine and cetirizine, unlike fexofenadine, were still superior in reducing eye symptoms compared to placebo. Phase II and III clinical trials (a total of 7 studies) involving 3,846 patients with allergic rhinoconjunctivitis also revealed the undeniable efficacy of bilastine compared to placebo. The difference in the effect on eye symptoms between bilastine and other comparable drugs - cetirizine, desloratadine - was not significant. Bilastine is characterized by a rapid onset of action (30-60 min) and a long-lasting effect (24 hours), making it convenient for patients to take once daily. Clinical studies have shown that when administering a therapeutic dose of 20 mg/day bilastine, the frequency of the most common adverse effects (drowsiness, headache, dizziness, fatigue) was almost the same as in the group of patients taking placebo. Bilastine is not metabolized in the liver and is excreted in the urine and feces. It is noteworthy that bilastine does not have clinically significant interactions with other drugs or alcohol. Reviewing effective symptomatic treatment methods for AR, it is necessary to mention the superior allergen-specific immunotherapy. This etiopathogenetic treatment method changes the natural course of the disease, helps to avoid new sensitization, and bronchial asthma. Allergen-specific immunotherapy is recommended for treating moderate to severe episodic and persistent AR. It is indicated when seasonal rhinitis recurs for 2 consecutive seasons or when persistent rhinitis lasts longer than six months and skin allergy tests or specific IgE in the blood are positive, correlating with the disease symptoms. Summary AR is a global problem. This disease significantly affects a person's social life, ability to learn, and work productivity. AR manifests with classic symptoms such as rhinorrhea, nasal itching, sneezing, nasal obstruction, but symptoms can also be atypical. Conjunctivitis symptoms often bother AR patients. AR diagnosis is based on history, nasal examination, skin allergy tests, and/or specific IgE determination in the blood. Treatment consists of allergen avoidance, pharmacotherapy, and specific immunotherapy. Oral second-generation H1 antihistamines play a significant role in treating AR. One of the newest drugs in this group, bilastine (Opexa®), effectively reduces all AR and related eye symptoms, is effective, and convenient for the patient to use without causing drowsiness. Journal "Internistas"
