Allergic Rhinitis

Clinical Snapshot

Allergic rhinitis is an IgE-mediated inflammatory response of the nasal mucosa to an inhaled allergen — pollen, dust mites, animal dander, or mold — producing sneezing, rhinorrhea, nasal and ocular itch, and congestion, frequently alongside allergic conjunctivitis.^[1]

An early phase driven by mast-cell degranulation and histamine release produces the itch, sneeze, and rhinorrhea symptom cluster within minutes of exposure; a later, eosinophil-driven inflammatory phase over the following hours is chiefly responsible for nasal congestion, which is why congestion often responds better to an anti-inflammatory intranasal corticosteroid than to an antihistamine alone.^[2]

The Allergic Rhinitis and its Impact on Asthma (ARIA) classification describes allergic rhinitis by symptom pattern (intermittent or persistent) and severity (mild or moderate-severe) rather than by season alone, since seasonal and perennial exposure patterns do not reliably predict either the duration or the severity of symptoms — see Choose Initial Treatment for the full classification and the treatment tracks it drives.

Recognize the Condition

Nasal and ocular symptoms

Nasal congestion, clear rhinorrhea, paroxysmal sneezing, and nasal itch are the hallmark symptoms, often with a sensation of postnasal drip. Ocular symptoms — itching, redness, tearing, and mild lid swelling (allergic conjunctivitis) — accompany nasal symptoms in most patients and can be as bothersome as the nasal symptoms themselves.

Physical examination findings

The nasal mucosa is typically swollen, pale, or bluish, and moist on examination with an ordinary otoscope. Other supportive findings include infraorbital edema and darkening ("allergic shiners"), a transverse nasal crease from repeated upward rubbing of the nose (the "allergic salute"), cobblestoning of the posterior oropharynx from chronic postnasal drip, and conjunctival redness or swelling.

Symptom pattern

Symptoms may follow a recognizable seasonal pattern tied to a specific pollen (tree, grass, or weed), or occur year-round (perennial), typically from indoor allergens such as dust mites, animal dander, or mold, flaring after specific exposures. See Choose Initial Treatment for how the ARIA intermittent/persistent and mild/moderate-severe classification is used to select therapy.

Risk Factors

Personal history of another atopic condition — asthma, atopic dermatitis, allergic conjunctivitis, or food allergy.
Family history of allergy or atopy.
Regular exposure to an environmental allergen the patient is sensitized to — seasonal (tree, grass, or weed pollen) or perennial (dust mites, animal dander, indoor mold).
Occupational allergen exposure (e.g., laboratory animals, flour, latex).
Concomitant use of ASA or NSAIDs, which can precipitate nasal symptoms in ASA-intolerant individuals.
Certain medications that cause or worsen nasal congestion independent of allergy — ACE inhibitors, sildenafil, and other phosphodiesterase-5 inhibitors among them.
Urban residence and higher-pollution environments.

Red Flags & Refer

Most red flags for allergic rhinitis are about recognizing when symptoms are not actually allergic rhinitis, or are no longer straightforward allergic rhinitis.^[1]

Unilateral nasal symptoms, unilateral nasal obstruction, or epistaxis out of proportion to the clinical picture — suggests a structural or neoplastic cause rather than allergic rhinitis.
Persistent facial pain or pressure — suggests sinusitis or another structural cause rather than uncomplicated allergic rhinitis.
Symptoms that do not respond to an adequate, adherent trial of appropriate first-line therapy — reassess the diagnosis rather than continuing to escalate allergy therapy indefinitely.
Signs of a complication, such as acute bacterial sinusitis, rather than uncomplicated allergic symptoms.
Inadequate symptom control despite adherence and correct technique with an antihistamine and an intranasal corticosteroid.
Adverse reactions to multiple allergy medications.
Reduced quality of life or impaired ability to function — sleep, school, or work — despite treatment.
A patient's desire to identify the specific sensitizing allergen(s) and receive environmental control advice.
Comorbid asthma with uncontrolled or recurrent upper airway symptoms, or recurrent sinusitis.
Candidacy for allergen immunotherapy.

Assessment & Diagnosis

Differentiating allergic rhinitis from its common mimics

Parameter	Allergic rhinitis	Viral upper respiratory infection	Vasomotor (non-allergic) rhinitis	Nasal polyps
Duration/pattern	Seasonal pattern, or perennial with exposure-related flares; intermittent or persistent per the ARIA classification	Self-limited, typically resolving within 7 to 10 days	Chronic or recurrent, triggered by nonallergic irritants	Chronic, progressive nasal obstruction
Itch/sneezing	Prominent — paroxysmal sneezing, nasal and ocular itch	Absent or minimal	Absent or minimal	Absent; anosmia is the dominant feature instead
Trigger	Specific inhaled allergen(s)	Viral infection; often associated with sore throat or fever	Irritants — smoke, temperature change, strong odours, cold air, exercise, spicy food	None specific; underlying chronic rhinosinusitis
Discharge	Clear rhinorrhea	Often becomes thicker and discoloured as the infection progresses	Profuse, watery rhinorrhea, often the dominant symptom	Variable; obstruction predominates
Nasal mucosa on exam	Swollen, pale or bluish, moist	Red, inflamed	Variable, often unremarkable	Visible polyp(s) on exam
Associated findings	Allergic shiners, transverse nasal crease, cobblestone pharynx, conjunctival symptoms	Sore throat, fever, malaise	None specific	Anosmia and reduced taste, almost universal

Local allergic rhinitis is a distinct, increasingly recognized entity: patients have classic allergic symptoms and a positive response to allergy-directed therapy, but negative skin-prick and serum-specific IgE testing — the allergic response is confined to the nasal mucosa itself and is only demonstrable with a nasal allergen challenge. Consider it when convincing allergic symptoms persist despite negative standard allergy testing, rather than concluding the symptoms are not allergic in origin. Non-allergic rhinitis is a broader category of nasal symptoms without an IgE-mediated mechanism, including vasomotor rhinitis (above), rhinitis of pregnancy, drug-induced rhinitis, and rhinitis medicamentosa from decongestant overuse — consider these when symptoms do not fit an allergic pattern or fail to respond to allergy-directed therapy.

History

Characterize symptoms — congestion, nasal itch, rhinorrhea, sneezing, postnasal drip, ocular symptoms — along with their frequency and severity.
Establish the duration and pattern of symptoms (intermittent versus persistent) to apply the ARIA classification.
Identify precipitating factors, including specific environmental allergens such as pollen and animal dander.
Ask about personal or family history of allergy or atopy.
Screen for comorbid conditions — sleep apnea or snoring, asthma, and conjunctivitis.
Take a medication history: intermittent ASA or NSAID use can precipitate nasal symptoms in ASA-intolerant individuals, and some drugs (ACE inhibitors, sildenafil, and other PDE5 inhibitors) can cause nasal congestion independent of allergy.
Ask about prior self-treatment, including over-the-counter products, and how well they controlled symptoms.

Physical examination

Examine the nasal mucosa (colour, anatomy) with an ordinary otoscope, and look for infraorbital edema (allergic shiners), conjunctival redness or swelling, a transverse nasal crease, cobblestoning of the posterior oropharynx, and evidence of postnasal drip.

Objective testing

Preferred testSkin-prick testing confirms allergic sensitization when present, helps identify causative allergens for avoidance counselling, and is generally preferred over serum-specific IgE testing unless a specific condition makes it unsatisfactory — widespread skin disease, or inability to temporarily stop antihistamine therapy. Antihistamines should be discontinued for at least 3 days before skin testing; tricyclic antidepressants, phenothiazines, and other drugs with antihistaminic activity (e.g., dimenhydrinate) may also interfere and should only be discontinued after discussing this with the patient's prescriber.^[1]

In vitro measurement of allergen-specific IgE (ELISA, previously performed as RAST) is an acceptable alternative but is more expensive and less sensitive than skin testing.

Not indicated: measuring total serum IgE has little diagnostic value, since it does not correlate well with the presence of allergic disease.

Treatment Targets

Prevent allergic symptoms from occurring by reducing exposure to the causative allergen(s).
Suppress and control the symptoms produced by the allergic response — nasal and ocular.
Avoid or minimize medication side effects, including any negative impact on daily activities.
Minimize interference with school or work performance and attendance, leisure activities, and sleep.

Choose Initial Treatment

Direct treatment rule

Classify by ARIA pattern first

The 2 ARIA treatment tracks

Intermittent, mild

Symptoms present under 4 days per week, or for under 4 consecutive weeks, AND normal sleep, no impairment of daily activities, sport, or leisure, normal work or school performance, and no troublesome symptoms.

Persistent, and/or moderate-severe

Symptoms present 4 or more days per week AND for 4 or more consecutive weeks (persistent), OR — regardless of duration pattern — 1 or more of: abnormal sleep, impairment of daily activities/sport/leisure, abnormal work or school performance, or troublesome symptoms present (moderate-severe).

Track 1 — intermittent, mild symptoms

1st line an oral second-generation antihistamine (e.g., cetirizine 10 mg PO once daily), used regularly during expected exposure or as needed, since these agents act quickly enough for on-demand use.^[3]

Alternative when congestion is the predominant symptom an intranasal corticosteroid even at this severity tier, since it outperforms an oral antihistamine specifically for nasal congestion.^[2]

Track 2 — persistent symptoms, and/or moderate-severe disease

1st line a regularly scheduled intranasal corticosteroid (e.g., fluticasone propionate 2 sprays per nostril once daily) — the single most effective medication class for allergic rhinitis, and consistently superior to an oral antihistamine or a leukotriene receptor antagonist, especially for congestion. Start 1 to 2 weeks before an expected, predictable exposure (e.g., a known pollen season) and continue daily rather than as-needed, since continuous use provides more effective symptom control.^[2]

Add for faster onset, or for breakthrough symptoms an intranasal antihistamine can be added to an intranasal corticosteroid, since its onset (minutes) is much faster than the 2 to 4 week maximal effect of an intranasal corticosteroid — particularly useful during the first 1 to 2 weeks of a new intranasal corticosteroid course.^[2]

Step up — inadequate control after a genuinely adherent 2 to 4 week intranasal corticosteroid trial with confirmed correct technique switch to a combination intranasal antihistamine/corticosteroid product (azelastine/fluticasone propionate, or olopatadine/mometasone furoate) rather than simply adding a separate oral antihistamine — the combination intranasal products have shown superior efficacy to either component used alone, while adding a separate oral antihistamine on top of intranasal corticosteroid monotherapy has not shown a clinically meaningful additional benefit.^[3]

Special situation — comorbid asthma or nasal polyps, or failure of first-line options a leukotriene receptor antagonist (montelukast) as monotherapy or as an add-on — a modest effect, similar to an oral antihistamine but less effective than an intranasal corticosteroid, so it is not a substitute for intranasal corticosteroid therapy as initial treatment.^[4]

Special situation — significant congestion despite regular intranasal corticosteroid use add an intranasal decongestant (oxymetazoline or xylometazoline) for a strictly time-limited course of no more than 3 to 7 days together with the intranasal corticosteroid, which mitigates the rebound-congestion risk that occurs with decongestant monotherapy — never use an intranasal decongestant alone, or beyond this window.^[4]

Special situation — very severe symptoms needing rapid control a short 5 to 7 day course of oral prednisone may be used while other therapy takes effect; this is a short-term bridge, never a maintenance strategy.

Avoid a first-generation (sedating) antihistamine as routine therapy for any severity tier — see Special Populations and Common Errors for the sedation and anticholinergic-burden rationale.^[5]

Non-Pharmacologic Treatment

Allergen avoidance

Pollen: use air conditioning to allow windows to stay closed, reducing exposure; nasal filters worn during high-exposure activities have demonstrated efficacy in reducing nasal and ocular symptoms in clinical trials.
Animal dander: removing pets from the home reduces perennial symptoms caused by that exposure.
Dust mites: impermeable covers for the mattress and pillows may reduce exposure; historical trial evidence for this measure has been mixed, though a more recent trial in dust-mite-allergic asthmatic children showed a reduction in asthma-related emergency visits over the following year. Acaricides (products that kill mites) have shown minimal added benefit in reducing symptoms, and the long-term safety of regular acaricide use on bedding is not established.

Saline nasal irrigation

Intranasal saline sprays or irrigation systems help relieve symptoms by washing out mucus and inhaled allergen. Use only distilled water, or water that has been boiled and cooled, to prepare the solution, and clean the irrigation device routinely.

Ocular symptom relief

Lubricant eye drops, or cold or warm compresses, can reduce conjunctival symptoms without medication.

Correct intranasal spray technique — a major factor in real-world efficacy

Aim the spray toward the outer wall of the nostril (the turbinates), angled upward and laterally toward the tip of the ear — never medially toward the septum, which increases irritation and epistaxis risk while reducing the dose actually delivered to the affected mucosa.

Most devices need initial priming before first use, and re-priming if not used for a product-specific interval (commonly several days to weeks) — confirm the specific product's requirement, since an unprimed or under-primed device delivers less than the full labelled dose.

Use on a fixed daily schedule rather than only when symptoms flare, since continuous, consistent use is substantially more effective than as-needed use for an intranasal corticosteroid.

For a combination intranasal antihistamine/corticosteroid product, tilt the head slightly forward, not backward, during administration — tilting the head back allows the medication to drip into the throat, producing an unpleasant taste.

Allergen immunotherapy

Allergen immunotherapy (subcutaneous or sublingual) is the only currently available disease-modifying option — a specialist-directed course of escalating allergen exposure that can produce sustained benefit lasting years after treatment is stopped, unlike symptomatic drug therapy. It is administered and monitored by an allergist/immunologist, not initiated in primary care or by a pharmacist. Refer a patient with confirmed IgE-dependent sensitivity to a specific allergen that cannot be effectively avoided, and whose symptoms are difficult to control with standard pharmacotherapy.

Pharmacologic Treatment Options

Drug / intervention	Role	Dose / use	Important adverse effects	Teaching points
Fluticasone propionate (nasal) Preferred	Intranasal corticosteroid, 1st line for persistent or moderate-severe disease	2 sprays (50 mcg/spray) per nostril once daily; may increase to twice daily for severe symptoms; maximum 400 mcg/day	Nasal burning/stinging, epistaxis	Aim away from the septum. Full effect takes 2 to 4 weeks of consistent daily use; continuous use outperforms as-needed dosing.
Mometasone (nasal) Preferred	Intranasal corticosteroid, alternative 1st-line agent	2 sprays (50 mcg/spray) per nostril once daily	Nasal burning/stinging, epistaxis	Unscented option; among the more reassuring intranasal corticosteroids for pregnancy and pediatric growth data.
Cetirizine Preferred	Oral 2nd-generation antihistamine, 1st line for intermittent/mild disease	10 mg PO once daily (5 mg if hepatic/renal impairment or age 65 and older)	Somnolence (more than other 2nd-generation agents, especially at higher dose), dry mouth, headache	Fast onset; can be used as needed or on a regular schedule during exposure.
Desloratadine Alternative	Oral 2nd-generation antihistamine	5 mg PO once daily	Headache, dry mouth	The only oral antihistamine specifically indicated for nasal congestion, though an intranasal corticosteroid remains more effective for this symptom.
Azelastine / fluticasone propionate Alternative	Combination intranasal antihistamine/corticosteroid, step-up after intranasal corticosteroid monotherapy failure or for faster onset	1 spray (137 mcg/50 mcg) per nostril twice daily	Bitter taste if the head is tilted back during administration, mild somnolence	Superior to either component alone for moderate-severe symptoms. Tilt the head forward, not back, during administration.
Olopatadine / mometasone furoate Alternative	Combination intranasal antihistamine/corticosteroid, moderate-severe seasonal disease with ocular symptoms	Ages 12 and older: 2 sprays (665 mcg/25 mcg) per nostril twice daily. Ages 6 to 11: 1 spray per nostril twice daily	Bitter taste, epistaxis, headache	Specifically indicated when ocular symptoms are prominent alongside nasal symptoms.
Montelukast Special situation	Leukotriene receptor antagonist, comorbid asthma/nasal polyps or failure of 1st-line options	10 mg PO once daily (5 mg ages 6 to 14; 4 mg ages 2 to 5)	Headache, flu-like symptoms; monitor for neuropsychiatric effects	Modest effect only, similar to an oral antihistamine but less than an intranasal corticosteroid — not a substitute for 1st-line therapy.
Oxymetazoline (nasal) Special situation	Intranasal decongestant, short-term add-on for congestion despite intranasal corticosteroid use	2 to 3 sprays per nostril every 12 hours as needed, maximum 2 doses per 24 hours, for no more than 3 to 7 days	Rebound congestion (rhinitis medicamentosa) with use beyond the recommended duration	Always pair with a concomitant intranasal corticosteroid, and counsel the patient on the strict duration limit before dispensing.
Diphenhydramine Avoid	First-generation oral antihistamine — routine use in allergic rhinitis is discouraged	25 to 50 mg PO every 4 to 6 hours	Sedation, anticholinergic effects (dry mouth, constipation, urinary retention), impairment the patient may not notice	A 2nd-generation agent is preferred for essentially every patient — see Special Populations and Common Errors.

Special Populations

Pregnancy: preferred initial therapy for nasal symptoms is a saline nasal spray or rinse. All antihistamines cross the placenta; cetirizine, loratadine, and — despite being first-generation — chlorpheniramine are each considered probably safe. Avoid oral decongestants during the first trimester given conflicting historical reports of possible malformation with first-trimester use; a short-term intranasal decongestant may be used instead. Intranasal corticosteroids have minimal systemic effect and are more effective than antihistamines or a leukotriene receptor antagonist, so risk-benefit considerations favour an intranasal corticosteroid as first-line pharmacotherapy in pregnancy specifically — beclomethasone and budesonide have the most reassuring historical pregnancy-safety data among the intranasal corticosteroids, with other agents considered generally safe given low systemic bioavailability but less pregnancy-specific data. One Canadian population-based study found an association between first-trimester intranasal triamcinolone use and an increased risk of respiratory-system birth defects, though a chance finding could not be excluded — prefer beclomethasone or budesonide when starting an intranasal corticosteroid during pregnancy. Montelukast is generally considered safe, though most supporting data come from animal models. Allergen immunotherapy should not be initiated during pregnancy given a lack of safety data, but may be continued, without dose escalation, in a patient already receiving it before conception.^[4]

Breastfeeding: preferred initial therapy is again a saline nasal spray or rinse. Second-generation antihistamines are generally considered safe, especially cetirizine and loratadine, along with intranasal and ophthalmic products; a theoretical reduction in milk supply is possible. Pseudoephedrine concentrates in breast milk, so a nasal decongestant is preferred over an oral one when a decongestant is needed — limit nasal decongestant use to a maximum of 5 days per episode. Intranasal corticosteroids are considered safe given low bioavailability. Montelukast concentrates in breast milk but is generally considered safe, and is commonly used directly in young children for asthma.

Pediatrics

Lower-volume nasal sprays (e.g., fluticasone furoate) tend to be better tolerated by children and are more effective than oral antihistamines for pediatric allergic rhinitis. If an antihistamine is used, a second-generation agent is strongly preferred, since sedating antihistamines are associated with drowsiness and learning impairment in children. Oral cough and cold preparations containing a decongestant, with or without a sedating antihistamine, should not be used in children under 6 years of age for allergic or viral rhinitis, per Health Canada's labelling decision based on limited efficacy evidence and reported adverse effects in this age group.^[6]

Intranasal corticosteroids and growth in children

Mometasone and fluticasone propionate have historically been favoured given low oral bioavailability and an absence of growth suppression with long-term use at recommended doses, though fluticasone propionate is scented and some children prefer an unscented product; mometasone and fluticasone furoate are both available unscented, and fluticasone furoate has the lowest spray volume of the intranasal corticosteroids. Budesonide dry-powder delivery is an alternative for a child who dislikes an aqueous spray, and had no measurable effect on growth at its standard once-daily dose in a controlled study. Growth suppression has been reported with high-dose beclomethasone (well above the standard recommended dose), with the lowest recommended dose of over-the-counter triamcinolone, and with double the usual approved pediatric dose of fluticasone furoate — whether this reduction is recovered over time is not established. Once-daily morning dosing may reduce growth-suppression risk relative to twice-daily dosing by more closely following the normal diurnal cortisol pattern, though comparative studies are still needed. Total corticosteroid burden should be considered when a child also uses an inhaled corticosteroid for asthma; regardless, always use the lowest effective intranasal corticosteroid dose in children.

Older adults

Avoid first-generation sedating antihistamines given anticholinergic burden, sedation, cognitive effects, and fall risk in this population.^[5] Among the second-generation agents, cetirizine is the most likely to cause some sedation, particularly at higher doses — consider a lower starting dose. Use oral or intranasal decongestants cautiously given a higher prevalence of hypertension, cardiovascular disease, benign prostatic hyperplasia, and hyperthyroidism in this population.

Hepatic and renal impairment

Reduce the starting dose of cetirizine to 5 mg daily in moderate hepatic or renal impairment, or in adults 65 years of age and older. Loratadine clearance is reduced in severe hepatic impairment — use a lower initial dose.

Monitoring & Follow-Up

Reassess symptom control 2 to 4 weeks after starting or escalating an intranasal corticosteroid, since maximal effect takes this long even though some benefit can appear on the first day of use. Before concluding that a therapy has failed, confirm adherence and correct spray technique. If as-needed antihistamine use has become effectively daily, consider switching to a regularly scheduled intranasal corticosteroid instead. Reassess the diagnosis, including for a non-allergic or drug-induced cause, if symptoms persist despite confirmed adherence to an appropriate first-line regimen. Monitor growth in children on long-term intranasal corticosteroid therapy, particularly with an agent or dose associated with growth suppression, and use the lowest effective maintenance dose. For any patient using an intranasal decongestant, ask specifically about frequency and duration of use at follow-up to catch early rebound congestion. For a patient with a predictable seasonal pattern, plan to restart an intranasal corticosteroid 1 to 2 weeks before the next expected exposure period. Monitoring for a patient on allergen immunotherapy is specialist-directed.

Treatment Failure / Next Step

Confirm adherence — was the medication actually used consistently as directed, particularly a daily intranasal corticosteroid rather than only as-needed use.
Confirm correct intranasal spray technique — aimed toward the outer wall of the nostril rather than the septum, and properly primed.
Reassess the diagnosis before assuming first-line therapy has failed — consider non-allergic rhinitis, local allergic rhinitis, vasomotor rhinitis, nasal polyps, rhinitis medicamentosa from decongestant overuse, or a drug-induced cause (an ACE inhibitor, a PDE5 inhibitor, or chronic ASA/NSAID use).
Step up per the treatment algorithm — switch to a combination intranasal antihistamine/corticosteroid product rather than empirically adding a separate oral antihistamine.
Add montelukast specifically if comorbid asthma or nasal polyps are present.
Consider a short 5 to 7 day course of oral prednisone for very severe breakthrough symptoms.
Refer to an allergist/immunologist per the criteria in Red Flags & Refer, including for consideration of allergen immunotherapy.

Common Errors to Avoid

Reaching for a first-generation sedating antihistamine as routine therapy, especially in older adults or in anyone whose occupation requires vigilance or concentration.
Using an intranasal decongestant for more than 3 to 7 days, or without a concomitant intranasal corticosteroid — both increase the risk of rebound congestion (rhinitis medicamentosa).
Expecting an intranasal corticosteroid to work immediately and abandoning it before a genuine, adherent 2 to 4 week trial.
Relying on an oral antihistamine alone when nasal congestion is the predominant symptom — an intranasal corticosteroid is more effective for congestion specifically.
Defaulting to a separate oral antihistamine as the step-up when an intranasal corticosteroid alone is inadequate, rather than a combination intranasal antihistamine/corticosteroid product with better supporting evidence.
Not counselling correct spray technique and aim — directing the spray at the septum increases irritation and epistaxis risk while reducing the dose delivered where it is needed.
Using an oral cough and cold combination product containing a decongestant and/or a sedating antihistamine in a child under 6 years of age.
Missing a drug-induced or non-allergic cause of nasal congestion — an ACE inhibitor, a PDE5 inhibitor, chronic decongestant overuse, pregnancy, or hypothyroidism — when antihistamines and an intranasal corticosteroid are not working.
Treating persistent unilateral symptoms, epistaxis, or facial pain as routine allergic rhinitis rather than investigating for a structural or neoplastic cause.
Overlooking local allergic rhinitis in a patient with convincing allergic symptoms but negative skin-prick or serum-specific IgE testing.

Clinical Decision Algorithm

Initial classification and treatment

Suspected allergic rhinitis: sneezing, rhinorrhea, nasal/ocular itch, congestion

Confirm diagnosis: history and exam; exclude red flags and consider differentials (viral rhinitis, vasomotor/non-allergic rhinitis, nasal polyps, local allergic rhinitis)

Red flags present

Investigate or refer per Red Flags & Refer rather than treating as routine allergic rhinitis

No red flags

Classify by ARIA pattern: intermittent/mild vs. persistent and/or moderate-severe

Intermittent, mild

Oral 2nd-generation antihistamine PRN or scheduled (e.g., cetirizine 10 mg PO daily), or an intranasal corticosteroid if congestion predominates

Persistent, and/or moderate-severe

Start a regularly scheduled intranasal corticosteroid (e.g., fluticasone propionate 2 sprays per nostril once daily)

Reassess after a genuine 2-4 week adherent trial with confirmed correct spray technique

Step-up for inadequate response

Inadequate control after a confirmed 2-4 week adherent intranasal corticosteroid trial with correct technique

Congestion or overall symptoms still inadequate

Switch to a combination intranasal antihistamine/corticosteroid (azelastine/fluticasone propionate, or olopatadine/mometasone furoate)

Comorbid asthma or nasal polyps

Add montelukast as an adjunct

Severe breakthrough congestion

Add a strictly time-limited course (3-7 days) of an intranasal decongestant together with the intranasal corticosteroid

Still uncontrolled, adverse reactions to multiple agents, reduced quality of life, or a desire for allergen identification: refer to an allergist/immunologist for consideration of immunotherapy

Drug Tables

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Intranasal corticosteroids

The mainstay of therapy for moderate-severe symptoms; more effective than an oral antihistamine or a leukotriene receptor antagonist, especially for congestion. A 2-4 week trial may be needed for maximal effect, though some benefit is often seen on the first day.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Beclomethasone dipropionate (nasal)	Adults and children 6 years and older: 2 sprays (50 mcg/spray) per nostril twice daily; maximum 12 sprays/day (adults) or 8 sprays/day (children); use the lowest effective maintenance dose	Nasal burning/stinging, epistaxis	None clinically significant at recommended intranasal doses	Slow onset (7-14 days for maximal effect). If excessive nasal mucus or mucosal edema is present, a short pretreatment course of an intranasal decongestant may improve delivery.
Budesonide (nasal)	Adults and children 6 years and older, aqueous spray: 2 sprays per nostril once daily, or 1 spray per nostril twice daily initially (64 mcg/spray); may decrease to 1 spray per nostril once daily for maintenance Adults and children 6 years and older, dry powder: 2 applications per nostril in the morning, or 1 application per nostril twice daily initially (100 mcg/dose); maximum 400 mcg/day	Nasal burning/stinging, epistaxis	None clinically significant at recommended intranasal doses	Also available as a dry-powder nasal inhaler for a patient who dislikes an aqueous spray; requires initial priming and re-priming if unused for 4 or more days.
Ciclesonide (nasal)	Adults and children 12 years and older: 2 sprays (50 mcg/spray) per nostril once daily; maximum 200 mcg/day	Nosebleeds, nasal irritation/dryness, headache, altered taste	None clinically significant at recommended intranasal doses	Pro-drug, activated locally in the nasal mucosa. Requires priming before first use and re-priming if unused for 4 or more days; discard 4 months after opening.
Fluticasone furoate (nasal)	Adults and children 12 years and older: 2 sprays (27.5 mcg/spray) per nostril once daily; maximum 110 mcg/day (4 sprays) Children 2 to under 12 years: 1 spray per nostril once daily, may increase to 2 sprays per nostril once daily if needed, then decrease to 1 spray per nostril daily for maintenance	Nasal burning/stinging, epistaxis	None clinically significant at recommended intranasal doses	Lowest spray volume of the intranasal corticosteroids; often preferred in children. Requires priming and re-priming if unused for 30 or more days.
Fluticasone propionate (nasal)	Adults and children 12 years and older: 2 sprays (50 mcg/spray) per nostril once daily, may increase to twice daily for severe symptoms; maximum 400 mcg/day Children 4 to 11 years: 1 to 2 sprays per nostril once daily; maximum 200 mcg/day	Nasal burning/stinging, epistaxis	None clinically significant at recommended intranasal doses	Scented formulation; some children prefer an unscented alternative.
Mometasone (nasal)	Adults and children 12 years and older: 2 sprays (50 mcg/spray) per nostril once daily Children 3 to 11 years: 1 spray per nostril once daily	Nasal burning/stinging, epistaxis	None clinically significant at recommended intranasal doses	Unscented. Also used at a high-dose regimen as an antibiotic-sparing option in some cases of acute rhinosinusitis — a separate indication from allergic rhinitis dosing.
Triamcinolone acetonide (nasal)	Adults and children 12 years and older: 2 sprays (55 mcg/spray) per nostril once daily, may decrease to 1 spray per nostril once daily for maintenance Children 4 to 11 years: 1 spray per nostril once daily	Nasal burning/stinging, epistaxis	None clinically significant at recommended intranasal doses	Available without a prescription in Canada. Its usual recommended dose, unlike some other intranasal corticosteroids, has been linked to reduced growth velocity in a pediatric study — use the lowest effective maintenance dose in children.

Second-generation (less-sedating) oral antihistamines

Preferred over first-generation agents for essentially every patient given a far lower sedation and anticholinergic burden.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Bilastine	Adults and children 12 years and older: 20 mg PO once daily Children 4 to 11 years, 16 kg or more: 10 mg PO once daily	Headache, dizziness, somnolence, upper abdominal pain; rare bradycardia	Serum levels increase up to 2-fold with ketoconazole; diltiazem can increase levels by about 50%. Take 1 hour before or 2 hours after meals or fruit juice, which can reduce absorption.	Not indicated under 4 years of age or under 16 kg body weight. No effect on driving performance shown in trials.
Cetirizine	Adults and children 12 years and older: 5 to 10 mg PO once daily; maximum 20 mg/day Children 6 to 11 years: 5 to 10 mg PO once daily Children 2 to 5 years: 2.5 mg PO once or twice daily	Somnolence (dose-related, more than other 2nd-generation agents), fatigue, dry mouth, headache	Additive CNS depression with alcohol or sedatives; additive anticholinergic effects with TCAs or scopolamine	A metabolite of hydroxyzine — avoid in patients with hydroxyzine hypersensitivity. Discontinue 3 days before allergy skin testing.
Desloratadine	Adults and children 12 years and older: 5 mg PO once daily Children 6 to 11 years: 2.5 mg PO once daily Children 1 to 5 years: 1.25 mg PO once daily	Headache, pharyngitis, dyspepsia; diarrhea reported more often in children	Pgp inhibitors (erythromycin, ketoconazole) may increase levels; Pgp inducers (carbamazepine, dexamethasone) may decrease levels, likely with minimal clinical effect	Discontinue 3 days before allergy skin testing.
Fexofenadine	Adults and children 12 years and older: 60 mg PO every 12 hours, or 120 mg PO once daily; maximum 120 mg/day Children 6 to 11 years: 30 mg PO twice daily	Headache, nausea	Aluminum- or magnesium-containing antacids and fruit juices (apple, grapefruit, orange) can decrease bioavailability	Renal impairment increases the risk of CNS side effects from drug accumulation.
Loratadine	Adults and children 10 years and older, over 30 kg: 10 mg PO once daily Children 2 to 9 years, 30 kg or under: 5 mg PO once daily	Headache, fatigue, dry mouth; nervousness/wheezing reported more often in children	QTc prolongation reported with concomitant amiodarone — use caution. Pgp inhibitors/inducers as with desloratadine.	Clearance decreased in severe hepatic impairment — use a lower initial dose. Take rapid-dissolve tablets on an empty stomach.
Rupatadine	Adults and children 12 years and older: 10 mg PO once daily Children 25 kg or more: 5 mg PO once daily Children 10 to 25 kg: 2.5 mg PO once daily	Somnolence, headache, tiredness, asthenia, dry mouth, nausea, dizziness	CYP3A4 inhibitors (erythromycin, ketoconazole, grapefruit juice) markedly increase levels — avoid combination; may need dose adjustment with CYP3A4 substrates (e.g., tacrolimus, cyclosporine)	Not recommended in renal or hepatic impairment given lack of data.

First-generation (sedating) oral antihistamines

Generally avoid as routine therapy given sedation and anticholinergic burden, especially in older adults or safety-sensitive occupations — see Special Populations. Included here for completeness and for the uncommon situation where a second-generation agent genuinely cannot be used.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Chlorpheniramine	Adults and children 12 years and older: 4 mg PO every 4 to 6 hours; maximum 24 mg/day Children 6 to 11 years: 2 mg PO every 4 to 6 hours; maximum 12 mg/day	Sedation, impaired cognition/performance (may be unrecognized by the patient), anticholinergic effects (dry mouth, constipation, urinary retention)	Additive CNS depression with alcohol/sedatives/barbiturates; additive anticholinergic effects with TCAs/scopolamine; CYP2D6 inhibitors (amiodarone, celecoxib, bupropion, paroxetine) can increase levels	Avoid in narrow-angle glaucoma, urinary retention/prostatic hypertrophy, and GI obstruction. Discontinue 3 days before skin testing. Give with food.
Diphenhydramine	Adults and children 12 years and older: 25 to 50 mg PO every 4 to 6 hours; maximum 300 mg/day Children 6 to 11 years: 12.5 to 25 mg PO every 4 to 6 hours; maximum 150 mg/day	Sedation, impaired cognition/performance (may be unrecognized by the patient), anticholinergic effects	Additive CNS depression with alcohol/sedatives/barbiturates; may increase levels of CYP2D6 substrates (e.g., metoprolol, venlafaxine)	Avoid in narrow-angle glaucoma, urinary retention/prostatic hypertrophy, and GI obstruction. Discontinue 3 days before skin testing.

Antihistamine/decongestant oral combinations

Avoid in severe hypertension or coronary artery disease; use with caution in cardiovascular disease, diabetes, hyperthyroidism, prostatic hypertrophy, and angle-closure glaucoma. Avoid combination products with additional ingredients such as analgesics or expectorants, which have not been shown to add benefit in allergic rhinitis.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Cetirizine / pseudoephedrine	Adults and children 12 years and older: 1 tablet (5 mg/120 mg) PO every 12 hours	Insomnia, tremor, irritability, palpitations, tachycardia, urinary retention, plus antihistamine effects (somnolence, dry mouth)	Contraindicated with MAOIs; reduces the antihypertensive effect of beta-blockers; avoid with phenothiazines/SSRIs
Desloratadine / pseudoephedrine	Adults and children 12 years and older: 1 tablet (2.5 mg/120 mg) PO every 12 hours	Insomnia, tremor, irritability, palpitations, tachycardia, urinary retention, plus antihistamine effects	Contraindicated with MAOIs; reduces the antihypertensive effect of beta-blockers
Fexofenadine / pseudoephedrine	Adults and children 12 years and older: 1 tablet (60 mg/120 mg) PO twice daily	Insomnia, tremor, irritability, palpitations, tachycardia, urinary retention, plus antihistamine effects	Contraindicated with MAOIs; antacids/fruit juice can decrease fexofenadine bioavailability	Take on an empty stomach.
Loratadine / pseudoephedrine	5 mg/120 mg formulation: 1 tablet PO twice daily 10 mg/240 mg formulation: 1 tablet PO once daily, preferably on waking	Insomnia, tremor, irritability, palpitations, tachycardia, urinary retention, plus antihistamine effects	Contraindicated with MAOIs; QTc prolongation reported with amiodarone

Oral decongestants

Drug	Dosage	Adverse effects	Drug interactions	Comments
Pseudoephedrine	Adults and children 12 years and older: 60 mg PO every 4 to 6 hours, or 120 mg sustained-release every 12 hours; maximum 240 mg/day Children 6 to 11 years: 30 mg PO every 4 to 6 hours as needed; maximum 120 mg/day; sustained-release formulations not recommended	Insomnia, tremor, irritability, headache, palpitations, tachycardia, urinary retention	Contraindicated with MAOIs (risk persists 2 weeks after stopping a nonselective MAOI); reduces the antihypertensive effect of beta-blockers; avoid with ergot derivatives	Sold from behind the pharmacy counter in Canada. Avoid in severe hypertension and coronary artery disease; caution in cardiovascular disease, diabetes, hyperthyroidism, and prostatic hypertrophy.

Note: oral phenylephrine's effectiveness for nasal congestion has not been well established, and — unlike pseudoephedrine — it is not available in Canada as a single-entity product or in combination with a less-sedating antihistamine.

Leukotriene receptor antagonists

Drug	Dosage	Adverse effects	Drug interactions	Comments
Montelukast	Adults and children 15 years and older: 10 mg PO once daily, in the evening Children 6 to 14 years: 5 mg PO once daily, in the evening Children 2 to 5 years: 4 mg PO once daily, in the evening	Headache, flu-like symptoms; monitor for neuropsychiatric effects (mood/behaviour changes, sleep disturbance)	Strong CYP2C9/3A4 inducers (carbamazepine, phenobarbital, phenytoin, rifampin) may decrease levels; strong CYP2C9 inhibitors may increase levels — clinical significance uncertain, monitor for reduced efficacy or adverse effects	Modest effect only — similar to an oral antihistamine but less effective than an intranasal corticosteroid. Consider as monotherapy or add-on specifically for comorbid asthma or nasal polyps, or after failure of first-line options.

Intranasal antihistamines

Faster onset than an intranasal corticosteroid (minutes rather than days), useful for breakthrough symptoms or the first 1-2 weeks of a new intranasal corticosteroid course.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Azelastine (nasal)	Typical monotherapy dosing where available: 1 to 2 sprays (137 mcg/spray) per nostril twice daily	Bitter taste, somnolence, nasal irritation, epistaxis	Additive CNS depression with alcohol or sedatives	In Canada, azelastine is most commonly used as the fixed-dose combination with fluticasone propionate (below); confirm current standalone product availability before dispensing.

Intranasal antihistamine/corticosteroid combinations

Shown to be superior to either component alone for moderate-severe symptoms; consider after intranasal corticosteroid monotherapy has failed a genuine trial, or when faster onset is important.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Azelastine / fluticasone propionate	Adults and children 12 years and older: 1 spray (137 mcg/50 mcg) per nostril twice daily	Bitter taste (dysgeusia) if the head is tilted back during administration, nosebleeds, mild somnolence	Avoid with ritonavir given potential for increased systemic corticosteroid effect	Authorized from 12 years of age. Tilt the head forward, not back, during administration.
Olopatadine / mometasone furoate	Ages 12 and older: 2 sprays (665 mcg/25 mcg) per nostril twice daily Ages 6 to 11: 1 spray per nostril twice daily	Bitter taste, epistaxis, headache	None clinically significant at recommended intranasal doses	Specifically indicated for moderate-severe seasonal allergic rhinitis with associated ocular symptoms. Authorized from 6 years of age.

Intranasal decongestants

Never use beyond the stated duration limit, and always counsel this limit explicitly before dispensing — see Choose Initial Treatment and Common Errors for the rebound-congestion rationale.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Oxymetazoline	Adults and children 12 years and older, 0.05%: 2 to 3 sprays per nostril every 10 to 12 hours as needed; maximum 2 doses/24 hours Duration limit: No more than 3 to 5 consecutive days	Transient burning/stinging/dryness of nasal mucosa; rebound congestion beyond the recommended duration	Contraindicated with MAOIs (risk persists 2 weeks after stopping a nonselective MAOI)	Use with caution in hypertension, diabetes, cardiovascular disease, prostatic hyperplasia, hyperthyroidism. Small accidental pediatric ingestions (1-2 mL) can cause serious toxicity.
Xylometazoline	Adults and children 12 years and older, 0.05% or 0.1%: 1 to 2 sprays or 2 to 3 drops per nostril every 8 to 10 hours as needed; maximum 3 doses/24 hours Duration limit: No more than 3 to 5 consecutive days	Transient burning/stinging/dryness of nasal mucosa; rebound congestion beyond the recommended duration	Contraindicated with MAOIs (risk persists 2 weeks after stopping a nonselective MAOI)	Use with caution in hypertension, diabetes, cardiovascular disease, prostatic hyperplasia, hyperthyroidism. Small accidental pediatric ingestions can cause serious toxicity.

Other intranasal therapies

Drug	Dosage	Adverse effects	Drug interactions	Comments
Ipratropium (intranasal)	Typical dosing: 2 sprays (21 mcg/spray, 0.03%) per nostril 2 to 3 times daily; optimal dose based on individual response	Nosebleeds, nasal dryness, dry mouth or throat, headache	None clinically significant	Reduces the volume of watery rhinorrhea; useful when rhinorrhea is the dominant or only symptom, or is refractory to an intranasal corticosteroid and/or antihistamine. This is a distinct nasal-spray formulation from the inhaled bronchodilator product of the same molecule used for asthma/COPD — confirm the intranasal 0.03% formulation specifically when dispensing.
Sodium cromoglycate (cromolyn), intranasal	Typical dosing where available: 1 spray per nostril, 4 times daily at regular intervals	Transient ocular/nasal stinging	None clinically significant	Excellent safety profile but less effective than an intranasal corticosteroid and requires 4-times-daily dosing; onset 4 to 7 days, with full benefit sometimes taking weeks. Not currently available in Canada.

Ophthalmic therapy for allergic conjunctivitis

Allergic conjunctivitis frequently accompanies allergic rhinitis; an oral or intranasal antihistamine, intranasal corticosteroid, or leukotriene receptor antagonist often improves ocular symptoms too, but a dedicated ophthalmic product can be added for insufficient relief.

Ophthalmic antihistamines and mast cell stabilizers

Drug	Dosage	Adverse effects	Drug interactions	Comments
Ketotifen (ophthalmic)	Adults and children 3 years and older: 1 drop in the affected eye(s) every 8 to 12 hours	Conjunctival injection, headache	None clinically significant	Dual antihistamine/mast-cell-stabilizer action; may be used for acute or chronic symptoms.
Olopatadine (ophthalmic)	Once-daily formulation, ages 12 and older: 1 drop in the affected eye(s) once daily Twice-daily formulation, ages 3 and older: 1 to 2 drops in the affected eye(s) every 12 hours	Mild transient burning/stinging, pruritus, hyperemia, photophobia, headache	None clinically significant	Dual antihistamine/mast-cell-stabilizer action; a once-daily (0.2%) or twice-daily (0.1%) formulation is available.
Lodoxamide (ophthalmic)	Adults and children over 2 years: 1 to 2 drops in the affected eye(s) 4 times daily at regular intervals	Mild transient discomfort on instillation — burning, stinging, itching, tearing	None clinically significant	Mast cell stabilizer only, no direct antihistamine effect; onset takes a few days, and treatment for up to 4 weeks may be needed for full benefit.
Sodium cromoglycate (ophthalmic)	Adults and children 5 years and older: 2 drops per eye, 4 times daily at regular intervals	Transient ocular stinging/burning	None clinically significant	Mast cell stabilizer only. Start at symptom onset; onset of improvement in 2 to 3 days. Discard within 1 month of opening.

Regular use of a topical ophthalmic vasoconstrictor (e.g., naphazoline, oxymetazoline, or phenylephrine eye drops) is discouraged given the risk of rebound vasodilation with continued use.

Short-course oral corticosteroid

For very severe nasal symptoms only, as a brief bridge while other therapy takes effect — never a maintenance strategy for allergic rhinitis.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Prednisone	Adults: 50 mg/day (or 0.5 mg/kg/day) PO for 5 to 7 days Children: 1 mg/kg/day PO, maximum 50 mg/day, for 5 days	Insomnia, mood changes, increased appetite, GI upset; longer courses risk adrenal suppression and other systemic corticosteroid effects	Numerous — review the full drug interaction profile before prescribing even a short course

Evidence note: drug inventory, dosing, adverse effects, and comments reflect standard Canadian practice, cross-checked against the current ARIA-EAACI and Rhinitis 2020 practice-parameter evidence base.^[4]^[1]

References

Allergic rhinitis — Allergy, Asthma & Clinical Immunology — Practical Guide for Allergy and Immunology in Canada 2024 (Rosenfield L, Keith PK, Quirt J, Small P, Ellis AK). Allergy Asthma Clin Immunol 2024;20(Suppl 3)
Allergic Rhinitis and Its Impact on Asthma (ARIA)-EAACI Guidelines-2024-2025 Revision: Part I-Guidelines on Intranasal Treatments — Allergy (Sousa-Pinto B, Bousquet J, Vieira RJ, et al.). Allergy 2026;81(4):954-976
Allergic Rhinitis and Its Impact on Asthma (ARIA)-EAACI Guidelines-2024-2025 Revision: Part II-Guidelines on Oral and Ocular Treatments — Allergy (Vieira RJ, Sousa-Pinto B, Bousquet J, et al.). Allergy 2026;81(6):1947-1970
Rhinitis 2020: A practice parameter update — Journal of Allergy and Clinical Immunology (Dykewicz MS, Wallace DV, Amrol DJ, et al.). J Allergy Clin Immunol 2020;146(4):721-767
CSACI position statement: Newer generation H1-antihistamines are safer than first-generation antihistamines for the treatment of allergic rhinitis and urticaria — Allergy, Asthma & Clinical Immunology (Fein MN, Fischer DA, O'Keefe AW, Sussman GL). Allergy Asthma Clin Immunol 2019;15:61
Health Canada reminds parents not to give cough and cold medication to children under 6 years old — Health Canada. Information Update, December 18, 2008 (archived)

Professional reference only. Apply clinical judgment and verify patient-specific decisions against current authoritative guidance and product information.