Allergic rhinitis: spring is worth remembering
Introduction
Allergic rhinitis (AR) is clinically defined as allergen-induced, immunoglobulin E (IgE)-mediated chronic inflammation of the nasal mucosa (1).
According to the World Allergy Organization, AR affects 10–30% of adults and up to 40% of children. In Europe, the prevalence ranges from 4% to 32%. AR is not limited to the nasal mucosa; patients frequently experience symptoms of other allergic conditions such as conjunctivitis, atopic dermatitis, and bronchial asthma. More than 40% of patients with AR are diagnosed with asthma, and more than 80% of individuals with asthma also have AR (2). Additionally, approximately 70% of patients with pollen-induced AR experience conjunctivitis (3).
AR is also associated with conditions such as sinusitis, nasal polyposis, recurrent upper respiratory tract infections, and serous otitis media (2). It is among the top ten reasons for visits to primary care physicians. Although AR is not usually life-threatening, it significantly affects quality of life, including social functioning, learning ability, and work productivity. The economic burden of the disease is also considerable (2, 4).
Risk factors for AR include a family history of atopic diseases, elevated total IgE levels in early childhood, positive skin prick tests indicating type I hypersensitivity, and higher socioeconomic status (2).
Classification of AR
According to current classification, AR is divided into intermittent and persistent forms based on symptom duration. Symptoms occurring less than four days per week or for less than four weeks are classified as intermittent AR, whereas symptoms occurring more than four days per week and lasting longer than four weeks are classified as persistent AR.
Based on severity and impact on quality of life, AR is categorized as mild or moderate-to-severe. Moderate-to-severe AR is defined by one or more of the following: sleep disturbances, impairment of daily, leisure, or sports activities, reduced work or school performance, and bothersome symptoms. Mild AR is characterized by the absence of these impairments (1).
Pathogenesis of AR
Allergic inflammation of the nasal mucosa involves the accumulation of T lymphocytes, mast cells, and eosinophils. It develops in three phases:
- Sensitization
- Early-phase reaction
- Late-phase reaction
Sensitization occurs during the initial exposure to an allergen. Specific IgE antibodies are produced and bind to mast cells.
Upon re-exposure, the allergen cross-links IgE on mast cells, leading to degranulation and release of mediators such as histamine. This results in acute symptoms, including sneezing, itching, rhinorrhea, and mild nasal congestion.
The late phase is characterized by the recruitment of inflammatory cells and the release of secondary mediators, leading to chronic symptoms such as nasal obstruction, hyposmia, and nasal hyperreactivity (4).
Ocular symptoms may occur due to the nasal–ocular reflex and local allergic inflammation of the conjunctiva (3).
In intermittent AR, often triggered by pollen, both phases are prominent. In persistent AR, chronic low-grade inflammation persists even in the absence of symptoms, emphasizing the importance of controlling inflammation rather than symptoms alone (1).
The early phase is effectively managed with antihistamines and mast cell stabilizers, while the late phase responds better to intranasal corticosteroids (1).
Etiology
AR is most commonly caused by inhaled allergens. Indoor allergens include house dust mites, animal dander, feathers, cockroaches, and molds. Outdoor allergens include tree, grass, and weed pollens, as well as seasonal fungal spores.
Up to 70–90% of individuals allergic to pollen also experience cross-reactivity to plant-based foods such as fruits, vegetables, and nuts. In Lithuania, peak pollen seasons are: trees in May, grasses in June, and weeds in August (1).
Clinical Features
Typical symptoms of AR include:
• rhinorrhea (anterior and/or posterior, clear discharge);
• nasal itching and frequent nose rubbing (“allergic salute”);
• sneezing;
• nasal obstruction, mouth breathing, snoring, sleep disturbances, and reduced sense of smell (1, 5).
Atypical symptoms, particularly in children, include:
• ear pain and hearing impairment due to Eustachian tube dysfunction;
• cough, often misdiagnosed as asthma;
• poorly controlled asthma due to untreated AR;
• sleep disturbances and fatigue;
• recurrent respiratory infections;
• oral allergy syndrome;
• rhinosinusitis with headache, facial pain, and purulent discharge (5).
Seasonal AR caused by pollen is known as hay fever (pollinosis) and is often associated with acute symptoms and conjunctivitis. Perennial AR, commonly caused by dust mites, is associated with chronic nasal symptoms (1).
Diagnosis
AR is diagnosed based on medical history, clinical examination, and diagnostic testing.
Confirmation is achieved through skin prick tests and/or measurement of allergen-specific IgE in serum. Nasal cytology may reveal eosinophilia. Additional diagnostic tools include nasal endoscopy, acoustic rhinometry, and imaging studies for suspected sinusitis (1, 5).
Treatment
Treatment of AR includes three main strategies:
• allergen avoidance;
• pharmacotherapy;
• allergen-specific immunotherapy.
Stepwise pharmacological treatment is recommended. First-line therapy for mild intermittent AR includes oral or intranasal H1 antihistamines. Decongestants may be used short-term for severe nasal obstruction.
For moderate-to-severe AR, intranasal corticosteroids are the most effective treatment. Additional options include leukotriene receptor antagonists and cromones.
For ocular symptoms, oral antihistamines, eye drops, and artificial tears are recommended.
Nasal saline irrigation is beneficial in all forms of rhinitis and may reduce the need for corticosteroids, particularly in children (5, 6).
Role of Antihistamines
Second-generation H1 antihistamines are preferred due to their improved safety profile, as they have minimal sedative and anticholinergic effects compared to first-generation agents (5, 6).
Bilastine (Opexa®) is one of the newer second-generation antihistamines. Clinical trials have demonstrated its efficacy and safety in treating AR and associated conjunctivitis.
In randomized controlled trials involving patients with seasonal allergic rhinoconjunctivitis, bilastine significantly reduced eye symptoms compared to placebo. Its effects were comparable to those of cetirizine and desloratadine.
Bilastine has a rapid onset of action (30–60 minutes) and a long duration of effect (24 hours), allowing once-daily dosing. It is not metabolized in the liver and has minimal drug interactions.
Immunotherapy
Allergen-specific immunotherapy is an effective etiological treatment that can alter the natural course of the disease and reduce the risk of developing asthma. It is recommended for patients with moderate-to-severe AR, particularly when symptoms persist despite pharmacological treatment.
Summary
Allergic rhinitis is a global health problem that significantly impacts quality of life. It is characterized by symptoms such as rhinorrhea, nasal itching, sneezing, and nasal obstruction, often accompanied by conjunctivitis.
Diagnosis is based on clinical history and allergen testing. Treatment includes allergen avoidance, pharmacotherapy, and immunotherapy. Second-generation antihistamines play a key role in symptom control.
Journal “Internistas”
