Viral Rhinitis

Viral rhinitis — the common cold — is a benign, self-limited infection of the upper respiratory tract caused by more than 200 different respiratory viruses, most often rhinovirus, followed by coronavirus, respiratory syncytial virus, adenovirus, parainfluenza virus, and enterovirus.^[1] Viral contact with the nasal mucosa triggers increased vascular permeability, glandular secretion, and vasodilatation — a direct inflammatory response, not a histamine-mediated allergic process — which is why drugs that help an allergic process (intranasal corticosteroids, second-generation antihistamines) generally do not help a cold, and why the drugs that do help here (decongestants, anticholinergic agents, first-generation antihistamines used for their anticholinergic effect) work through a different mechanism entirely. Symptoms typically peak around day 2-4 and resolve within 7-10 days without treatment, though cough can persist up to 3 weeks in a substantial minority of patients; no available treatment shortens the underlying illness or prevents complications such as otitis media or bacterial rhinosinusitis — every therapy discussed in this chapter is purely symptomatic.

Typical presentation

Onset is gradual over 1-2 days. A sore throat is often the earliest symptom and usually resolves within a few days, followed by nasal congestion, rhinorrhea, sneezing, and cough. Nasal discharge often becomes thicker and discoloured (yellow or green) as the illness progresses, as neutrophils are recruited to the mucosa — this reflects the normal inflammatory course of a viral infection, not bacterial superinfection, and is not on its own a reason to suspect or treat a bacterial cause. Fever is infrequent in adults but common in children. Symptoms peak around day 2-4 and begin resolving by day 7; the full course usually runs 7-10 days, though cough can persist up to 3 weeks in some patients.

Viral replication peaks within 48 hours of infection, but shedding can continue for up to 3 weeks — a patient can remain contagious well after feeling better.

• Close contact with an infected person, particularly hand-to-hand contact — the dominant transmission route for rhinovirus.
• Young age — children average considerably more colds per year than adults.
• Daycare or school attendance, and other crowded settings.
• Fall, winter, and early spring seasons (rhinovirus peaks in fall/spring; coronavirus peaks in mid-winter/early spring); less common in summer.
• Tobacco or e-cigarette use, or second-hand smoke exposure.
• Immunocompromising conditions, which can prolong or worsen the course of illness.

Distinguishing viral rhinitis from its mimics

Viral rhinitis, allergic rhinitis, influenza, and COVID-19 can all present with nasal and respiratory symptoms early on, but the correct management differs substantially between them.

History

• Symptom timeline and trajectory (gradual onset, peak day 2-4, expected improvement by day 7) — a course that does not fit this pattern should prompt reconsideration of the diagnosis.
• Associated symptoms: sore throat, cough, fever, ear pain, facial/sinus pain, wheeze.
• Screen specifically for the red flags above at every assessment.
• Vaccination status (influenza, pneumococcal, COVID-19), exposure history, and comorbidities that increase complication risk (asthma, COPD, immunocompromise, young infant age).

Examination

• Vital signs, including temperature — a genuinely high fever or tachypnea should prompt reconsideration of the diagnosis rather than reassurance.
• Ear exam in children, given the risk of otitis media as a complication.
• Oropharynx and neck exam if sore throat or lymphadenopathy is prominent, to screen for streptococcal pharyngitis or another cause.
• Chest auscultation if cough is prominent, to screen for wheeze or localized findings that would suggest a different diagnosis.

Investigations

• No laboratory or imaging investigation is needed for a straightforward, uncomplicated presentation — this is a clinical diagnosis.
• Consider influenza and/or COVID-19 testing per current local public health/testing guidance when the result would change management (e.g., antiviral candidacy in a high-risk patient) or is needed for public health purposes.
• Reserve chest x-ray, sinus imaging, or bloodwork for patients meeting red-flag criteria — these are not routine tests for viral rhinitis.

• Relieve nasal congestion and rhinorrhea.
• Reduce pain, headache, and fever.
• Reduce cough, particularly when it disrupts sleep.
• Minimize interference with work, school, and daily activities.
• Minimize the adverse effects of whatever therapy is chosen — match the specific agent to the specific bothersome symptom rather than defaulting to a multi-symptom combination product.
• Limit person-to-person transmission through hand and cough hygiene.

• Maintain usual fluid intake to stay hydrated; there is no evidence that increasing fluid intake beyond normal improves recovery, but adequate hydration remains reasonable general advice.
• Rest as needed, though no studies specifically support this recommendation.
• Hand hygiene and cough/sneeze etiquette (into the elbow or a tissue that is then discarded) are the most effective measures to limit transmission to others.
• Avoid close contact with others while symptomatic, particularly during the first few days of illness.
• A mask or face covering in public settings may be reasonable to reduce transmission.
• Steam inhalation has insufficient evidence to recommend it and carries a real burn risk, particularly in children — advise caution if a patient chooses to try it, and ensure any vaporizer is cleaned regularly to prevent contamination.

Saline nasal irrigation

Saline nasal irrigation (0.9% NaCl) is a genuinely evidence-supported, low-risk, nonpharmacologic option — it may reduce nasal secretions and congestion and reduce the need for decongestants, in both children and adults.^[9] Breast- or bottle-fed infants, who are obligate nose breathers, may particularly benefit from regular saline nasal drops to aid nasal clearance and improve mucociliary function.

Natural health products — an honest evidence review

Several natural health products are commonly asked about for cold treatment; the evidence for each is modest at best, and none should be presented to a patient as a reliably effective option.

• Zinc lozenges — a 2024 Cochrane review found that zinc supplementation may modestly shorten the duration of a cold, but the effect is inconsistent across studies and comes with an increased rate of adverse effects (chiefly unpleasant taste and nausea); dosing and duration have not been established with enough consistency to make a specific product recommendation.^[10]
• Vitamin C — routine supplementation once a cold has started has not been shown to shorten its duration or reduce its severity in the general population; there is insufficient evidence to recommend it as a treatment.^[11]
• Echinacea — evidence for both prevention and treatment is weak and inconsistent; not recommended.
• North American ginseng extract (e.g., Panax quinquefolius) — some evidence supports a modest reduction in the total time with upper respiratory symptoms when taken preventatively for several months before cold season, but there is insufficient evidence to recommend it once a cold has already started, and no safety data exist for children.
• Topical menthol/camphor preparations — not recommended in children under 2 years of age, and should never be applied directly under or in the nostrils at any age, given the risk of increased mucus production and reduced clearance leading to respiratory distress in children; camphor specifically carries a toxicity risk if ingested or misused.
• Probiotics — some evidence supports a modest reduction in upper respiratory infection frequency when taken for several months as a preventive measure, not as treatment once symptoms have started.

Pregnancy

Fever associated with a cold or influenza during pregnancy has been associated with an increased risk of certain birth defects, which is one reason to treat fever promptly in this population rather than letting it run its course.

First-generation antihistamines (brompheniramine, chlorpheniramine, diphenhydramine) are considered safe in pregnancy.

Oral decongestants (phenylephrine, pseudoephedrine) have conflicting reports of a possible small increase in specific malformations with first-trimester use — more evidence is needed before a clear recommendation can be made, so avoid routine first-trimester use and prefer a topical option if a decongestant is genuinely needed.

Topical decongestants (oxymetazoline, xylometazoline) are considered safe for short-term use (a maximum of 3-5 days) in pregnancy, although systemic absorption has not been fully characterized and some systemic effects (hypertension, respiratory depression, sedation) have been reported with xylometazoline specifically.

Acetaminophen is the preferred agent for fever, headache, and discomfort in pregnancy. Avoid NSAIDs in late pregnancy — risk of premature closure of the ductus arteriosus in the third trimester, and a potential reduction in amniotic fluid after 20 weeks' gestation.

High-dose vitamin C supplementation is not recommended in pregnancy for this self-limited condition — combined high-dose vitamin C and vitamin E supplementation has been associated with a higher incidence of intrauterine growth restriction in trial data evaluating pre-eclampsia prevention, which raises enough uncertainty that it should not be recommended for a self-limited illness like a cold. The safety of Echinacea in pregnancy has not been established, and ginseng's active component has shown teratogenic potential in animal studies — advise caution with both.

Breastfeeding

Intranasal saline and topical decongestants (oxymetazoline, xylometazoline) are preferred over oral decongestants during breastfeeding.

Honey is safe during breastfeeding — there is no risk of transferring botulism toxin to the breastfeeding infant through breast milk.

First-generation antihistamines and pseudoephedrine are generally considered safe during breastfeeding, but watch for infant drowsiness or irritability, and be aware that these agents — especially in combination — can reduce serum prolactin and milk supply; use the lowest effective dose and duration, and discontinue if a decrease in milk supply is observed.

Acetaminophen is the preferred agent for fever, headache, and discomfort during breastfeeding; NSAIDs are also considered safe.

Use Echinacea and ginseng with caution during breastfeeding given insufficient safety data.

Pediatrics

The pediatric age restrictions in Choose Initial Treatment above are the single most frequently tested pharmacist counselling point for this condition — non-prescription cough and cold products (antihistamines, decongestants, antitussives, expectorants) should not be used under 6 years of age, opioid-containing cough/cold products should not be used under 18 years of age, and honey should be avoided under 12 months of age because of infant botulism risk.^[6]

ASA should never be used in a child or adolescent with a viral illness because of the risk of Reye syndrome — a rare but serious hepatic and neurologic illness strongly associated with aspirin use during a viral infection in this age group; acetaminophen or ibuprofen are the appropriate alternatives.^[12]

In school-aged children (6 years and older), there have been few trials of antihistamine/decongestant use; weigh the risks of treatment carefully against the modest evidence of benefit before recommending routine use, even though these products are not restricted by age in this group the way they are under 6.

Older adults

Use decongestants (oral more than topical) with caution given a higher prevalence of hypertension, cardiovascular disease, diabetes, and benign prostatic hyperplasia in this population.

Avoid first-generation antihistamines (diphenhydramine, chlorpheniramine, brompheniramine) where possible — the Beers Criteria specifically recommend against this drug class in adults 65 years and older because of markedly increased confusion, delirium, and fall risk from the anticholinergic burden.

Set expectations at the outset: symptoms typically peak by day 2-4 and improve by day 7, with the full course usually resolving within 10-14 days; cough specifically can persist up to 3 weeks in a substantial minority of patients even when everything else has resolved.

1. Confirm the diagnosis still fits: reassess the timeline (symptoms should be improving by day 7, resolved within 10-14 days) and re-screen for red flags — a course that does not fit this pattern is the first sign this may not simply be a cold that has not cleared yet.
2. Reassess specifically for a secondary bacterial complication — acute otitis media (especially in a child with new ear pain), bacterial rhinosinusitis (unilateral facial pain, pain on bending forward, symptoms worsening after initial improvement), or pneumonia (fever, tachypnea, localized chest findings) — and manage on the relevant condition-specific pathway rather than escalating cold therapy.
3. Confirm the patient is not still using a topical decongestant beyond 3-5 days — rebound congestion (rhinitis medicamentosa) from overuse can itself masquerade as a cold that will not go away, and the fix is discontinuation (sometimes with gradual withdrawal), not more decongestant.
4. Review every product the patient is using for unintentional acetaminophen or NSAID double-dosing — a common cause of an adverse effect being mistaken for treatment failure, particularly when a combination cough/cold product is being used alongside a separate analgesic.
5. If symptoms genuinely persist beyond 3 weeks without a clear alternative explanation, or recur frequently, consider allergic rhinitis, chronic rhinosinusitis, or another chronic process rather than continuing to treat as an unusually long single cold episode.

• Recommending or prescribing an antibiotic for an uncomplicated cold — discoloured nasal discharge reflects the normal inflammatory course of a viral infection, not bacterial superinfection, and is not on its own an indication for antibiotics.^[8]
• Letting a patient continue a topical intranasal decongestant beyond 3-5 days — the single most common preventable error in cold management, causing rebound congestion that is often worse than the original problem.^[13]
• Recommending a combination cough/cold, antihistamine, or decongestant product for a child under 6 years of age.^[6]
• Recommending or dispensing an opioid-containing cough/cold product (e.g., codeine) for anyone under 18 years of age.^[7]
• Missing unintentional acetaminophen or NSAID double-dosing when a patient combines a multi-symptom combination product with a separate, single-ingredient analgesic — always ask what else the patient is already taking before recommending an additional product.
• Recommending ASA for fever or pain in a child or adolescent with a viral illness — Reye syndrome risk.^[12]
• Framing a first-generation antihistamine's benefit for a cold as blocking an allergy — the mechanism here is anticholinergic drying, not antihistamine action against an allergic process, and the wrong expectation undermines informed consent about the sedation trade-off.
• Overlooking saline nasal irrigation as a genuinely evidence-supported, essentially risk-free option, in favour of reflexively recommending a decongestant.^[9]
• Missing a secondary bacterial complication in a patient whose course is biphasic (initial improvement, then worsening) rather than simply prolonged — this pattern is a specific red flag, not just a cold taking longer than usual.

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.

Analgesics and antipyretics

Anticholinergics, nasal

Antihistamines, first-generation (oral)

Modest benefit at best, through an anticholinergic drying effect rather than blocking an allergic process -- sedation is a common trade-off.

Decongestants, nasal (topical)

Limit every agent in this class to a maximum of 3-5 consecutive days to avoid rebound congestion (rhinitis medicamentosa).

Decongestants, oral

There is no published evidence supporting oral decongestant, antihistamine, or antihistamine/decongestant combination use in children under 6 years of age.

Decongestant/antihistamine combination products

Combination antihistamine-decongestant-analgesic products show, at best, a modest overall improvement in feeling unwell compared with placebo, without clear evidence of benefit for individual symptoms, and an increased rate of adverse effects -- favour single-ingredient, symptom-targeted therapy over these products whenever practical.<cite data-reference-id="a9581179-aa08-41ea-8e9c-f68d5658410a"></cite> For any combination product, dose according to the specific active-ingredient content stated on that product's label rather than assuming a standard dose -- strengths vary widely between brands. The core counselling risk with this whole category is unintentional double-dosing: many of these products already contain acetaminophen or ibuprofen, so confirm a patient is not adding a separate analgesic on top.

Antitussives and expectorants -- insufficient evidence for the common cold

Dextromethorphan, codeine, and guaifenesin are not routinely recommended for cold-associated cough given insufficient evidence of benefit specific to this condition; if a cough suppressant is genuinely wanted despite this, the pediatric restrictions above still apply in full.

Honey

The single best-supported option for bothersome cough in an eligible patient.