Synopsis
Distinguish self-limiting viral upper-respiratory infection from influenza and bacterial or lower-respiratory complications, using targeted antiviral treatment and safety-netting rather than routine antibiotics.
- Most acute coryzal illnesses are viral and improve with supportive care; purulent nasal discharge alone does not prove bacterial infection or justify antibiotics.
- Influenza more often causes abrupt fever, myalgia, headache, profound malaise and dry cough, but clinical features overlap with COVID-19 and other respiratory viruses.
- Assess severity and host risk: pregnancy, older age, immune suppression and chronic cardiac, respiratory, renal, hepatic or neurological disease increase complication risk.
Key red flags
Dyspnoea, hypoxaemia, pleuritic pain, focal crackles or recurrent fever after initial improvement suggests viral pneumonitis or secondary bacterial pneumonia.
Investigation priorities
Identify influenza, SARS-CoV-2 or another virus when the result changes treatment or infection control.
Management branches
Symptoms remain confined to the upper airway with stable observations, hydration and no high-risk host factor.
- Explain the likely viral course, review analgesic contraindications and advise fluids, rest, hand hygiene and respiratory etiquette.
- Avoid routine antibiotics and low-value testing, while considering COVID-19 or influenza testing when current public-health or treatment rules make it useful.
Key medicines
OseltamivirUsual adult treatment is 75 mg orally twice daily for five days, with renal adjustment and specialist extension for selected cases.
ParacetamolUse 500 mg to 1 g orally up to four times daily, maximum 4 g in 24 hours for most adults.