Allergic Rhinitis

Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip.

Differentials:

Differential Diagnosis:

• Non-Allergic Rhinitis:
  • Chronic rhinosinusitis, vasomotor rhinitis.
• Exclusion of Red Flags:
  • Unilateral nasal obstruction, progressive blood-stained discharge, malodorous nasal discharge, or unilateral polyps warrant further evaluation.

Mechanism of Allergic Rhinitis:

• Sensitization:
  • Triggered by exposure to airborne allergens, such as dust mites, pollens (tree, grass, weed), animal dander, and mould.
  • Allergen exposure leads to production of allergen-specific IgE antibodies.
  • IgE binds to mast cells and basophils in nasal mucosa.
• Re-Exposure:
  • Subsequent allergen exposure results in cross-linking of IgE antibodies.
  • Mast cell degranulation releases histamine and inflammatory mediators.
• Phases:
  • Immediate/Early Phase: Histamine-driven, causing rhinorrhoea, sneezing, itching, nasal congestion.
  • Late Phase: Involves eosinophils/inflammatory cells, leading to chronic symptoms such as nasal obstruction, hyposmia, mucosal hyper-reactivity.

Epidemiology:

• Global Prevalence: Ranges from 5% to 50% worldwide, often underdiagnosed.
• Australian Context (2017–18): Affects approximately 1 in 5 individuals.
• Age Distribution: Peaks between ages 25–44; children often underdiagnosed due to inability to articulate symptoms.

Clinical Impact:

• Quality of Life Impairment:
  • Significant impact on daily activities, work/school productivity, sleep quality, mood, and concentration.
• Paediatric Considerations:
  • May present with sleep-disordered breathing, snoring, behavioural issues, and frequent upper respiratory tract infections.
• Co-Morbidity with Asthma:
  • 60–80% of individuals with AR also have asthma, necessitating concurrent management.

Risk/Protective Factors:

• Risk Factors:
  • Genetic predisposition (family history of atopy).
  • Childhood atopy, including eczema.
  • Higher socioeconomic status.
• Unclear Factors:
  • Early allergen exposure (e.g., dust mites, pollen) and pollution have inconclusive evidence regarding their contribution to AR.
  • Higher prevalence noted in urban, polluted areas compared to rural regions.
• Protective Factors:
  • Evidence supports the protective role of breastfeeding and microbial diversity.

classification

While this classification is useful for specific treatments such as allergen avoidance and immunotherapy, in practice, nonallergic and allergic rhinitis often co-exist

These may be difficult to differentiate as skin prick tests can be positive in 25–30% of
healthy young adults and 30–35% of healthy children

An alternative classification system based on symptom severity and frequency
has been proposed and is useful in treatment decision making

Coexistence of Nonallergic and Allergic Rhinitis:

• Differentiation can be difficult as skin prick tests are positive in up to 25-35% of healthy individuals.
• Symptom-based classification (severity, frequency) aids in treatment decisions.

Key History Points in Assessment:

• Symptom Onset:
  • Determine if rhinitis is seasonal (e.g., rye grass hay fever typically peaks during spring and early summer) or perennial.
  • Seasonal rhinitis is more commonly seen in school-aged children and young adults, while perennial rhinitis tends to affect preschool-aged children.
• Nasal Discharge Characteristics:
  • Assess if discharge is watery, bloody, discolored, or unilateral. Such characteristics may suggest conditions other than allergic rhinitis.
• Comorbidities:
  • Evaluate for co-existing conditions like asthma (present in ~50% of rhinitis patients), rhinoconjunctivitis (seen in ~70%), and eczema.
• Allergen Exposure:
  • Inquire about housing conditions, pets, and occupational or environmental exposures.
  • In children, explore potential food allergies, as they may co-occur with allergic rhinitis.
• Medication History:
  • Consider whether symptoms may be induced by current medications.
• Quality of Life Impact:
  • Assess the effects of symptoms on sleep quality, daytime fatigue, snoring, school or work performance, and social activities.

Important History Questions:

• Age of Symptom Onset: Helps differentiate between seasonal (common in school-aged children/young adults) and perennial forms (more common in preschool children).
• Symptom Timing: Does rhinitis occur year-round or seasonally? For example, grass pollen-related hay fever generally occurs during spring and early summer (6–8 weeks).
• Nasal Discharge: Determine if the discharge is unilateral or bilateral, and whether it is watery, bloody, or discolored. Watery or unilateral discharge may indicate non-allergic or structural conditions.
• Associated Symptoms:
  • Cough, wheezing, itchy or red eyes, and skin symptoms may indicate a broader allergic condition (e.g., asthma or eczema often co-exist with allergic rhinitis).
• Medication and Treatment History: Review previous treatments and assess the patient’s adherence to long-term management plans.
• Allergen Exposure History: Consider household pets, occupational exposure, and housing conditions. In young children, diet and food allergies should be assessed.
• Impact on Daily Life:
  • Discuss the effect of symptoms on sleep (including snoring and daytime sleepiness), school/work performance, and participation in social activities.

Physical Examination:

• Facial Inspection:
  • Look for signs of allergic rhinitis such as ‘allergic shiners’ (dark circles under the eyes) and a transverse nasal crease caused by frequent upward rubbing of the nose (the “allergic salute”).
• Nasal Airflow Assessment:
  • Ask the patient to close their mouth and breathe through their nose onto a metal surface (e.g., a stethoscope arm) to evaluate airflow. Unequal condensation suggests partial obstruction, likely due to swollen turbinates or a deviated septum.
• Nasal Examination with Auriscope:
  • Assess the size of inferior turbinates, nasal mucosa appearance, nasal septum position, and check for nasal polyps.
  • In cases of previous epistaxis, check for dilated vessels in Little’s area.
• Throat Examination:
  • Inspect for large tonsils, which may indicate lymphoid hypertrophy and possible adenoidal involvement.
  • Postnasal drip (mucus in the oropharynx) may suggest upper airway pathology such as rhinosinusitis.

Investigations:

Skin Prick Testing:

• Gold standard for allergen-specific diagnosis.
• A positive result is defined as a skin wheal measuring ≥3 mm, indicating sensitization or the presence of IgE antibodies to the allergen.
• However, this does not confirm that the allergen is the direct cause of symptoms.
• Indiscriminate ordering of large allergen panels can lead to confusion and unnecessary lifestyle modifications. Test results should always be interpreted alongside clinical history to ensure relevance.
• Clinical Example:
  • A patient presents with symptoms limited to early spring. Skin testing shows negative results for rye grass but positive results for house dust mite. Since house dust mite exposure is perennial, this suggests the symptoms may be nonallergic.

Serum Allergen-Specific IgE Testing:

• Accessible and useful for confirming sensitization to suspected allergens.
• Positive results from RAST tests must be considered carefully to avoid misinterpretation.
• Testing should be guided by the patient’s history rather than broad, indiscriminate panel testing.
• A mismatch between clinical symptoms and test results or a lack of response to treatment should prompt consideration of alternative diagnoses.
• Laboratory Considerations:
  • Medicare rebates available for limited allergen panels.
  • Important to consider medication cessation before testing (e.g., withholding antihistamines).

Management of Allergic Rhinitis

Patient Education

Provide comprehensive education to patients regarding their condition and management options to promote adherence and symptom relief.

Allergen Avoidance and Minimisation

Encourage patients to avoid or minimise exposure to known or likely allergens as much as possible.

Nasal Douching

• Regular nasal douching helps cleanse the nasal cavity of stagnant mucus, reducing allergen burden within the mucus.
• This can alleviate symptoms and improve the effectiveness of other treatments.

Saline Nasal Spray

• Use four times daily during the acute phase of symptoms.
• Once symptoms are controlled, reduce use to twice daily for maintenance.

Decongestants

• Short-term use only; risk of rebound congestion (rhinitis medicamentosa).

Intranasal Steroids

• Regular use of intranasal steroids is highly effective, particularly when combined with nasal douching. Administer the steroid spray 15 minutes after nasal douching for optimal results.
• While generally considered safe for long-term use, it is advisable to use the lowest effective dose to maintain symptom control.
• Beclomethasone has been associated with growth effects in children when used for one year; this has not been observed with fluticasone or mometasone.
• Treatment adherence may be compromised due to local side effects such as dryness, irritation, or epistaxis (commonly caused by incorrect application and targeting Little’s area).

Commonly Used Intranasal Steroids:

• Beclomethasone: 50 µg/dose, two sprays twice daily (S2)
• Budesonide: 32 µg/dose (S2) or 64 µg/dose, one to two sprays per nostril daily (S4)
• Ciclesonide: 50 µg/dose, two sprays per nostril daily (S4)
• Fluticasone Propionate: 50 µg/dose, one spray per nostril daily (S2)
• Fluticasone Furoate: 27.5 µg/dose, one spray per nostril daily (S4)
• Mometasone: 50 µg/dose, one spray per nostril daily (S2)

Non-Sedating Antihistamine Nasal Spray

• Useful for breakthrough symptoms, such as sneezing and watery eyes.
• Common Options:
  • Azelastine: 125 µg/dose, one spray per nostril twice daily (S2)
  • Levocabastine: 0.5 mg/mL, two sprays per nostril twice daily (S2)

Combination Nasal Sprays

• Dymista (Fluticasone Propionate 50 µg/dose + Azelastine 125 µg/dose)
  • Adults and Adolescents (≥12 years): One spray per nostril twice daily (morning and evening).
  • Children (6-11 years): One spray per nostril twice daily (morning and evening).

Referral to an Immunologist/Allergist

• Consider referral for immunotherapy if symptoms are insufficiently controlled with the above measures.

Immunotherapy

• Appropriate for patients whose symptoms are not well-managed through pharmacological and conservative measures.
• Subcutaneous Immunotherapy (SCIT):
  • Most effective but highest risk of systemic reactions.
• Sublingual Immunotherapy (SLIT):
  • Safer, self-administered, suitable for children.

Surgical Intervention

• indicated for significant anatomical obstruction (e.g., septal deviation, turbinate hypertrophy).
• Does not address underlying allergic tendency.
• Consider surgery for inferior turbinate hypertrophy if conservative measures fail.

(S2: Over the counter; S4: Prescription only)

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When to suspect nonallergic causes

Mismatch between allergy test results and clinical presentation:

• Indicates nonallergic rhinitis.

Mismatch between degree of airflow obstruction and diameter of nasal airway on inspection:

• Possible Cause: Adenoidal hypertrophy (e.g., inferior turbinates do not appear swollen, airway appears patent, but airflow is restricted).

Unilateral obstruction:

• Structural causes: Deviated septum, enlarged turbinates, nasal polyps.

Persistent unilateral discharge in children:

• Possible Cause: Foreign body.
• Rare Cause: Watery unilateral discharge may indicate cerebrospinal fluid leak.

Persistent mucopurulent discharge +/- facial pain:

• Possible Cause: Chronic rhinosinusitis or superimposed infection.

Nasal crusting:

• Possible Causes:
  • Staphylococcus aureus infection.
  • Nose picking.
• In adults, severe crusting suggests: Connective tissue disease.

Loss of sense of smell:

• Possible Causes: Chronic sinusitis or nasal polyps.

Failure to respond to medical treatment for allergic rhinitis:

• Possible Causes:
  • Nonadherence to treatment regimen.
  • Reconsider diagnosis, including any of the causes listed above.