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KembaraXtra- Medicine – Allergic Rhinitis
Allergic rhinitis (AR) is an immunoglobulin E (IgE)–mediated hypersensitivity reaction to inhaled environmental allergens that leads to inflammation of the nasal mucosa. This inflammatory process is driven primarily by type 2 helper T (Th2) cells and results in the characteristic symptoms of sneezing, rhinorrhea, nasal pruritus, and nasal congestion. Allergic rhinitis may be seasonal, triggered by pollens, or perennial, caused by year-round allergens such as dust mites, molds, and animal dander.
Allergic rhinitis is highly prevalent, affecting 10% to 30% of the U.S. population and up to 40% of children, with substantial impact on quality of life, school performance, and workplace productivity. The mean age of onset is between 8 and 12 years, and approximately 80% of cases develop before age 20. Sensitization to aeroallergens is uncommon before the age of one year. Among patients presenting to primary care with nasal complaints, allergic rhinitis accounts for 30% to 60% of cases.
Clinically, allergic rhinitis is distinguished from nonallergic rhinitis by the presence of sneezing, nasal itching, and ocular pruritus. Both allergic and nonallergic rhinitis may cause nasal congestion, postnasal drip, and cough. Additional symptoms include fatigue, irritability, reduced sense of smell, and a sensation of ear fullness. Physical examination often reveals pale or violaceous, edematous nasal turbinates caused by venous engorgement, a feature that helps distinguish allergic rhinitis from viral rhinitis, which typically presents with erythematous mucosa. Other findings may include clear nasal discharge, posterior pharyngeal drainage, conjunctival injection, throat erythema, and occasionally nasal polyps.
The most common triggers of allergic rhinitis include pollens (trees in spring, grasses in summer, and weeds in fall), as well as dust mites, mold spores, and animal allergens. Nonallergic irritants such as smoke, strong odors, and pollution may exacerbate symptoms in both allergic and nonallergic rhinitis but do not represent the primary mechanism of disease.
Diagnosis is largely clinical, based on history and physical examination. Many patients do not require formal diagnostic testing if symptoms and triggers are typical. A seasonal pattern of symptoms can help identify the likely allergen source, whereas year-round symptoms suggest perennial allergens. Allergy testing, either by skin testing or serum-specific IgE testing, may be useful in patients with persistent symptoms despite standard therapy, those considering allergen immunotherapy, or when precise identification of allergens is necessary for avoidance strategies.
Management begins with nonpharmacologic measures, including allergen avoidance when feasible. Strategies include dust mite control with mattress and pillow encasements, removal of carpeting and allergen-collecting items from the bedroom, use of HEPA air filtration, and limiting exposure to pets in sensitized individuals. Nasal saline sprays or irrigations are effective adjunctive therapies that reduce nasal dryness, congestion, and allergen load.
For pharmacologic treatment, intranasal corticosteroids are the preferred first-line therapy for most patients with allergic rhinitis. These agents effectively reduce nasal inflammation and improve all major symptoms, although maximal benefit may take at least one week of regular use. In patients with moderate to severe disease, combination therapy with an intranasal corticosteroid and an intranasal antihistamine provides greater symptom control than either agent alone. Oral second-generation antihistamines may be helpful for persistent ocular symptoms but offer little additional benefit when combined with intranasal corticosteroids for nasal symptoms. Montelukast should be reserved for patients who cannot tolerate or do not respond to first-line therapies, and intranasal ipratropium may be considered when rhinorrhea is the predominant complaint.
For patients with persistent or severe symptoms despite optimal medical therapy, allergen immunotherapy may be considered. Both subcutaneous and sublingual immunotherapy can significantly reduce symptoms and medication use, with approximately 80% of patients reporting improvement. Immunotherapy is contraindicated in patients with uncontrolled asthma, a history of severe reactions to immunotherapy, and—specifically for sublingual therapy—those with eosinophilic esophagitis.
Overall, the prognosis of allergic rhinitis is excellent. Most patients achieve good symptom control with appropriate avoidance strategies and medical therapy. Referral to an allergist or otolaryngologist is appropriate for patients with moderate to severe disease, those unresponsive to treatment, or individuals interested in immunotherapy.
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