Allergic Rhinitis Overview and Impacts

Allergic and Nonallergic Rhinitis - Summary

• Incidence of chronic rhinitis has significantly increased in recent decades, especially in Western countries.
• Moderate to severe rhinitis negatively impacts work and school performance, contributing to substantial indirect economic costs.
• Rhinitis contributes to the development and severity of other disorders, including asthma, sinusitis, middle ear disease, and dental malocclusion.
• Allergic rhinitis and idiopathic rhinitis are the two most prevalent rhinitis syndromes. IgE assessment distinguishes the two.
• Some rhinitis cases are locally allergic, without systemic IgE evidence.
• Allergy immunotherapy is the only treatment altering disease progression, improving long-term nasal symptoms and reducing asthma risk.

Epidemiology - Incidence and Prevalence

• Allergic disease prevalence increased since the late 1980s.
• International Study of Asthma and Allergies in Childhood (ISAAC), Phase 1 (1992), investigated allergic disease prevalence across continents in nearly 60 countries.
• ISAAC Phase 1 rhinitis prevalence in 6- to 7-year-olds ranged from 0.8% to 14.9% (median 6.9%).
• ISAAC Phase 1 rhinitis prevalence in 13- to 14-year-olds ranged from 1.4% to 39.7% (median 13.6%).
• Prevalence rates were highest in Western Europe, North America, and Australasia; lowest in Eastern Europe, and South/Central Asia.
• Phase 3 ISAAC analyses reveal increased rhinitis prevalence, with median 12-month rates of 8.5% (6- to 7-year-olds) and 14.6% (13- to 14-year-olds).
• Significant prevalence increases were noted in 67% of 6- to 7-year-old studies, 45% of 13- to 14-year-old studies.
• Prevalence trends suggest rising rhinitis incidence, mostly in developed nations with improved living standards.

Epidemiology - Risk Factors

• Several factors in early childhood influence rhinitis development.
• Gender may play a role, with females showing slightly higher rhinitis incidence.
• Studies on outdoor air pollution and rhinitis development produced mixed results.
• Parental smoking, particularly maternal smoking, significantly increases rhinitis risk in children.
• Presence of siblings and daycare use are inversely correlated with rhinitis risk (protective factors).
• Airborne allergen exposure may have a protective role.
• A negative correlation exists between grass pollen counts and adult-onset allergic rhinitis.
• Dietary factors, especially the Mediterranean diet, may protect against rhinitis and asthma development.

Quality of Life and Economic Impact

• Chronic rhinitis significantly impairs health-related quality of life.
• Measures like SF-36 show substantial reductions in physical functioning, energy, general health perception, social functioning, emotions, mental health, and pain in moderate-to-severe perennial allergic rhinitis patients, compared to controls.
• Sleep disruption, nasal obstruction, and concentration problems are noted as specific symptoms impacting quality of life.
• Rhinitis also affects cognitive function and mood, especially during allergy seasons.
• Reduced work productivity and increased absenteeism are associated with rhinitis.

Associated Diseases

• Asthma is present in approximately 40% of patients with chronic rhinitis.
• Over 80% of asthma patients also have persistent nasal symptoms.
• Similar inflammation mediators and cellular infiltrations connect rhinitis and asthma.
• Elevated airway inflammation and bronchial hyper-responsiveness are common in allergic rhinitis patients with no clinical asthma.
• This nasal disease significantly increases asthma complications (emergency room visits and hospitalizations).
• Allergic rhinitis is an independent risk factor for asthma development.

Diagnosis - History

• Common symptoms include congestion, sneezing, rhinorrhea, and nasal pruritus/itching.
• Congestion often alternates between nasal sides (nasal cycle).
• Unilateral obstruction suggests anatomical problems (septal deviation, nasal polyps, tumors).
• Explosive sneezing patterns are observed
• Clear/white rhinorrhea is typical; purulent discharge suggests rhinosinusitis or atrophic rhinitis.
• Eye symptoms are common (redness, itching, watering) impacting treatment choice.
• Other symptoms like headaches, facial pressure, smell loss, cough, or bad breath should also be noted.

Diagnosis - Physical Examination

• Routine examination assesses nasal structure (deformities, bony fractures) and potential comorbidities (conjunctivitis, otitis, asthma, skin conditions).
• Examination assesses bilateral nasal obstructions, asymmetry, and outward signs of prior trauma (children).
• Nasal cavity interior is closely examined using otoscopes or nasal speculums.
• Topical decongestant (phenylephrine) may be used to reduce mucosal swelling.
• Paleness or redness, presence/consistency of secretions are key to examining the nasal mucosa.

Diagnosis - Laboratory & Diagnostic Tests

• Allergy testing (IgE testing) for identifying allergic rhinitis compared to nonallergic.
• Nasal cytology (smears) is used to distinguish allergic rhinitis from nonallergic and from sinusitis.
• Blood eosinophils and total serum IgE are elevated in allergic rhinitis, although overlap with healthy individuals limits diagnostic value.
• Radiographic imaging (CT scan) is used to assess sinus tissue health specifically if symptoms aren't typical.
• Nasal Patency measurements assess nasal airway for swelling and objective symptom evaluation.

Classification of Rhinitis Syndromes

• Allergic rhinitis (50% of cases), is triggered by airborne allergens.
• Symptoms include congestion, watery discharge, sneezing and pruritus (nose, palate, throat, eyes).
• Nonallergic rhinitis encompasses diverse subtypes, primarily based on their etiologies.
• Importantly, there's variability in reported nasal inflammation.

Pathophysiology - Mechanisms of Rhinitis Symptoms

• Sneezing and pruritus are often caused by neural activation due to irritants or inflammatory byproducts.
• Rhinorrhea results from excessive stimulation of nasal glands that produce mucus.
• Nasal congestion is caused by venous sinusoid engorgement in the nasal mucosa, a process possibly linked to sympathetic or parasympathetic neural activation and/or inflammatory mediator discharge.