Allergic Rhinitis

Condition

Affects 19% of the Australian population, commonly between ages 25–44. Strongly associated with asthma and eczema.

Common allergens: tree pollen (spring) and grass pollen (summer); moulds; house dust mites (perennial rhinitis); hair/fur/feathers (cats, dogs, horses, birds); some foods (cow’s milk, eggs, peanuts).

History

Sneezing; nasal obstruction and congestion; hypersecretion (watery rhinorrhoea, postnasal drip); reduced sense of smell; itchy nose (usually allergic); dry/sore/itchy throat; irritated eyes.

Classify by pattern: intermittent (<4 days/week or <4 weeks) vs persistent (≥4 days/week for ≥4 weeks). Classify by severity: moderate/severe involves troublesome symptoms, sleep disturbance, or impairment of activities.

Investigations

Detection of allergen-specific IgE antibodies (not specific). RAST testing or skin testing for specific allergens (can give false negatives).

Management

Stepwise approach, reviewed after 2–4 weeks:

• Intermittent, or persistent with mild symptoms: oral or intranasal antihistamine.
• Persistent with moderate-severe symptoms: intranasal corticosteroid, alone or combined with an antihistamine. If rhinorrhoea is prominent, add intranasal ipratropium. Consider montelukast as an alternative or add-on.
• Ongoing troublesome symptoms despite the above: review the diagnosis, consider allergy testing if not already done, and consider referral to an immunologist for desensitisation (subcutaneous or sublingual immunotherapy).

Drug options:

• Antihistamine — e.g. loratadine 10mg once daily (5mg if <30kg, 2.5mg if <2 years).
• Intranasal antihistamine — e.g. azelastine 1mg/mL, 1 spray each nostril twice daily.
• Intranasal steroid — e.g. fluticasone (furoate 27.5mcg or propionate 50mcg) 2 sprays once daily initially, then 1 spray daily maintenance. Combination corticosteroid + antihistamine sprays (e.g. azelastine + fluticasone, available since 2014) are a convenient single-device option once monotherapy is inadequate.
• Montelukast — adults 10mg daily; children 2–5 years 4mg daily; children 6–14 years 5mg daily.

Sublingual immunotherapy (SLIT) — wafers/tablets for specific allergens (e.g. house dust mite, grass pollen) are now available as an alternative to injectable desensitisation for appropriate patients, usually initiated by an immunologist/allergist.

Screening tool: CARAT-10 (Control of Allergic Rhinitis and Asthma Test) is a validated patient-completed questionnaire that can help assess symptom control and prompt treatment step-up in general practice.