When should I consider prescribing antibiotics for a patient with acute sinusitis?

Consider prescribing antibiotics for acute sinusitis only if:

• Symptoms have lasted for more than 10 days without improvement, or symptoms worsen after an initial milder phase (double sickening), suggesting a bacterial cause is more likely.
• There is severe localized pain (often unilateral, especially over teeth and jaw), discoloured or purulent nasal discharge, or fever greater than 38°C.
• The patient is systemically very unwell, has signs of a more serious illness, or is at high risk of serious complications due to pre-existing comorbidities.
• Symptoms worsen rapidly or significantly despite initial management, or there is no improvement after 10 days of antibiotic treatment.

In these cases, consider prescribing phenoxymethylpenicillin as first-line in adults unless there are life-threatening symptoms or high risk of complications, where co-amoxiclav is preferred. For penicillin allergy, clarithromycin or doxycycline may be used.

Otherwise, antibiotics are generally not recommended immediately; a back-up (delayed) antibiotic prescription may be offered when bacterial infection is suspected, with advice to start antibiotics only if symptoms do not improve within 7 days or worsen significantly.

Self-care with analgesics (paracetamol or ibuprofen) and nasal saline or decongestants may be advised initially.

Immediate antibiotic prescribing is not recommended for most cases as acute sinusitis is usually viral and self-limiting.

Refer to specialists if immunocompromised, suspected allergic/immunological causes, anatomical defects, or recurrent/severe cases.

All prescribing decisions should be accompanied by safety-netting advice and patient education on symptom management and when to seek further help.

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