Diagnosis

When to suspect allergic rhinitis

Allergic rhinitis is easily missed. Consider the possibility of allergic rhinitis in a patient with any of the following:

Symptoms suggestive of continuous or recurrent upper respiratory tract infections
Frequent sore throats
Hoarse voice
Persistent throat-clearing
Persistent mouth breathing, especially in children with perennial rhinitis
Snoring
Feeling of pressure over sinuses
Recurrent headaches
Recurrent serous otitis media, especially in children
Coughing, especially in children (e.g. those who habitually cough soon after lying down at night)
Halitosis
Poor sleep and daytime fatigue or poor concentration
Loss of sense of smell
Persistent respiratory symptoms despite stable, well controlled asthma, appropriate treatment and good lung function on spirometry.

Practice points

Patients can mistake symptoms of allergic rhinitis for asthma. Allergic rhinitis is sometimes more easily recognised only after asthma has been stabilised.
The absence of classical symptoms does not rule out the diagnosis of allergic rhinitis. It may present as any combination of rhinorrhoea, itching/sneezing and blockage, including blockage alone.
Children with allergic rhinitis may show persistent throat-clearing but be unaware of nasal symptoms.

History

Ask about:

symptoms (runny nose, sneezing, blocked nose, itchy/runny eyes)
onset, duration and pattern of symptoms over the day or year (Table 1)
family and personal history of allergic conditions, e.g. asthma, atopic dermatitis
triggering and relieving factors
use of medications (including complementary medications), adherence and response
home, work and leisure environments
any systemic symptoms (e.g. daytime fatigue).

! Further investigations/early referral (or specialist consultation where referral access is limited) may be indicated if any of these are present:

Difficult-to-treat eczema, food allergies or poorly controlled asthma >> Consider referral to allergy specialist.
Persistent rhinitis symptoms that have not responded to a trial of appropriate medications >> Consider referral to allergy specialist or ear, nose and throat surgeon (ENT).
Persistent symptoms and signs suggesting chronic sinusitis (nasal obstruction, congestion, post nasal drip and a reduced sense of smell¹⁸) for 12 weeks or more >> Consider CT scan, referral to allergy specialist or ENT. >> Consider foreign body.
Atypical symptoms that suggest an alternative diagnosis such as polyp, tumour, or foreign body (e.g. persistent unilateral bleeding, persistent unilateral obstruction) >> Consider referral to ENT.

Practice points

Pollens and moulds are typically seasonal allergens in southern regions, but can be perennial in tropical northern regions (see Australasian Society of Clinical Immunology and Allergy pollen calendars at www.allergy.org.au).
The majority of patients are sensitised to multiple allergens (e.g. both pollens and house dust mite), so symptoms may be present throughout the year.
Both rhinitis and asthma can be triggered by the same factors, whether allergic (e.g. house dust mite, pet allergens, pollen, cockroach) or non-specific (e.g. cold air, strong odours, environmental tobacco

Pharmacy practice points

Advise people with asthma to consult their GPs for thorough investigation if:
rhinitis symptoms are severe or not well controlled by INCS and antihistamines
rhinitis treatment is required for more than 4 weeks at a time
other medical conditions are present
there are any complications, e.g. pain, hearing loss, loss of sense of smell.

Physical Examination

Examine upper and lower airway for signs of rhinitis and for signs of asthma. In addition to the nasal cavity (including inspection of mucosa and septum), examine the eyes and orbital areas, ears and oropharynx, perform a thorough chest examination.

Further investigation should be considered if:

asthma is suspected (or status of existing asthma control needs review) >> Perform pre-and post-bronchodilator spirometry.
a unilateral polyp is present (see History) >> Consider referral to ENT.

The absence of abnormal findings does not exclude intermittent allergic disease.

Practice points

It is reasonable and practical to make a provisional diagnosis of allergic rhinitis in a patient with suggestive symptoms and treat accordingly, provided that the diagnosis is reassessed if the patient does not experience prompt resolution of symptoms in response to treatment.

Confirm cause is predominantly allergic

Try to distinguish allergic rhinitis from common non-allergic types (e.g. vasomotor rhinitis, bacterial and viral respiratory infections, sinusitis). Up to 80% of Australian young adults with rhinitis symptoms are atopic.¹⁹
Rule out less common conditions, (e.g. overuse of topical decongestant sprays, nasal polyps, anatomical abnormalities, foreign bodies, adverse effects of medications, hormonal effects, sensitivity to drugs or occupational irritants, cocaine abuse) and rare conditions (e.g. tumours, granulomas, atrophic rhinitis, ciliary defects, cerebrospinal rhinorrhoea, vocal cord dysfunction).

Be aware that both allergic and non-allergic components may contribute to rhinitis in an individual.

Practice points

Before contemplating allergen avoidance measures or discussing desensitisation therapy, confirm which allergens are clinically important. Consider referral to an allergist for detailed allergy assessment.
Tell patients:
– Food allergies do not cause allergic rhinitis – nasal symptoms in reaction to food (e.g. spicy foods, wine) is not due to allergy but may indicate irritation or a chemical intolerance.
– Rhinitis in response to fumes (e.g. fragrances and paints) is not an allergic reaction, though it may respond to INCS.

Initiate a therapeutic trial with INCS

Give INCS and monitor response in patients with:

a provisional diagnosis of persistent allergic rhinitis
no features requiring immediate referral or further investigations
no contraindications to use of intranasal corticosteroids (severe nasal infection including candidiasis, haemorrhagic diathesis, history of recurrent nasal bleeding).

If symptoms do not resolve within a 3–4 weeks of commencing INCS, consider allergy testing and review the diagnosis.

If symptoms respond and long-term (>6 weeks) treatment is required, confirm a definitive diagnosis of allergic rhinitis through careful history and appropriate allergy testing.

Practice points

Both allergic and non-allergic rhinitis can respond to INCS.² Therefore response to INCS alone does not confirm allergy or warrant allergen avoidance measures in the absence of confirmed allergic triggers.

Consider allergy testing, referral

Skin prick testing or blood tests for allergen-specific IgE (radioallergosorbent testing; RAST) may be necessary to identify triggers.

These tests should be interpreted by a doctor trained in their interpretation. False negative and false positive results can occur.
Refer to an allergist if triggers are in doubt.
Most rural and remote areas can access RAST through major pathology laboratories.