Acute and chronic rhinosinusitis

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Acute rhinosinusitis commonly follows a viral upper respiratory infection. Swelling impairs sinus ventilation and mucus clearance, producing obstruction, discharge, reduced smell and facial discomfort. The duration and trajectory matter: deterioration after an initial improvement, marked unilateral localised pain, fever and purulent discharge may increase the likelihood of bacterial involvement, but no single feature proves that antibiotics will help. Explain the expected two-to-three-week course so that persistence for a few days is not mistaken for treatment failure.

Chronic rhinosinusitis is a persistent inflammatory syndrome, generally lasting at least twelve weeks, with two or more sinonasal symptoms including blockage or discharge, often with smell loss or facial pressure. Specialist examination and, when appropriate, imaging establish objective disease and distinguish cases with and without nasal polyps. Chronic symptoms are not an indication for repeated short empirical antibiotic courses. Treatment instead centres on local anti-inflammatory therapy, saline, associated airway disease and correction of selected structural or surgical problems.

Key points

An uncomplicated acute episode usually lasts two to three weeks, and most patients do not need antibiotics.
Symptoms for around ten days or less generally warrant supportive care with explicit deterioration advice.
After at least ten days without improvement, consider a fourteen-day high-dose intranasal corticosteroid course in adults and children aged twelve or over.
A no-antibiotic or back-up strategy remains appropriate for many patients with prolonged symptoms who are not systemically very unwell.
Give immediate antibiotics for systemic illness or high complication risk, while hospital red flags override community prescribing.
Chronic rhinosinusitis involves symptoms for at least twelve weeks and needs evaluation of persistent inflammation, polyps and alternative diagnoses.
Facial pressure alone does not establish sinus disease; consider migraine, dental infection and structural nasal problems.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Viral and bacterial episodes

Most acute episodes accompany viral respiratory infection. Secondary bacterial infection is more likely with a prolonged or worsening course, but clinical features overlap and antibiotic benefit remains modest in uncomplicated illness.

Persistent inflammatory disease

Chronic rhinosinusitis has several inflammatory phenotypes and may coexist with allergy, asthma or nasal polyps. Dental disease, impaired clearance and selected structural factors can contribute to persistent or localised symptoms.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Impaired sinus drainage
Mucosal swelling narrows drainage pathways and disrupts mucus clearance. Retained secretions and pressure contribute to obstruction and discomfort, without proving that a bacterial pathogen is responsible.
2
Sustained mucosal inflammation
In chronic disease, continuing inflammation alters the mucosal environment and may promote polyp formation. The persistent mechanism explains the role of topical treatment beyond an individual episode of discharge.
3
Spread beyond the sinuses
Infection can extend through adjacent bone or venous connections into the orbit or intracranial structures. Visual or neurological symptoms therefore change both the urgency and the required treatment setting.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Acute symptom trajectory

Record onset, progression and any second deterioration after early improvement. Ask specifically about fever, severe localised pain and systemic wellness. A patient with mild symptoms on day twelve is different from one developing orbital pain on day three.

Chronic symptom cluster

Ask how long obstruction, discharge and reduced smell have persisted, and whether there are symptom-free intervals. Persistent smell loss or bilateral visible polyps supports an inflammatory phenotype; isolated recurrent facial pain should prompt consideration of headache disorders.

Dental and unilateral disease

Upper dental pain, recent dental procedures, offensive discharge or persistent unilateral maxillary symptoms can indicate a dental source. Examine the mouth and arrange appropriate dental or ENT evaluation rather than repeating nasal treatments.

Complication screen

Assess visual symptoms, ocular movement, swelling around the eye, forehead swelling and neurological state. Severe pain with immunosuppression or poorly controlled diabetes warrants a lower threshold for urgent specialist assessment, including invasive infection.

Red flags requiring action

New eye swelling with diplopia, restricted movement or visual change requires immediate hospital assessment for orbital spread.
Severe frontal headache, forehead swelling, meningism, altered consciousness or focal neurological signs require emergency assessment for intracranial complications.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Clinical assessment without routine imagingFirst step
Why
Identify uncomplicated acute disease and exclude immediate complications.
Interpretation and limitations
Typical acute symptoms can usually be managed on history and examination. Routine sinus radiographs or CT do not determine whether a mild episode needs an antibiotic and add little to initial care.
02
Nasal endoscopy for persistent or atypical disease
Why
Look for objective inflammation, polyps and a unilateral lesion.
Interpretation and limitations
ENT assessment can identify mucosal changes or discharge beyond anterior inspection. Findings must be interpreted with symptom duration; a symptom label alone does not establish chronic inflammatory disease.
03
CT of the sinuses when specialist assessment indicates
Why
Define persistent disease extent or plan an intervention.
Interpretation and limitations
CT is useful for selected chronic disease, surgical planning or suspected complications. Incidental mucosal thickening is common and must not replace clinical correlation.
04
Urgent imaging and laboratory investigations for complicated disease
Why
Assess orbital or intracranial extension and guide inpatient treatment.
Interpretation and limitations
The receiving team selects contrast imaging, blood tests and cultures according to suspected spread. Normal inflammatory markers do not safely exclude a dangerous complication when eye or neurological signs are present.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Migraine and other headache disorders

Recurrent facial pressure with headache, light sensitivity or nausea may reflect migraine, particularly when nasal findings are limited. Sinus imaging abnormalities alone do not establish the explanation for pain.

Odontogenic infection

Dental pathology can produce unilateral maxillary symptoms and offensive discharge. Identifying and treating the dental source is necessary when antibiotics or nasal medication would otherwise provide only temporary improvement.

Rhinitis or structural narrowing

Allergic inflammation, turbinate enlargement and septal deviation can cause obstruction without chronic sinus disease. Symptom duration, associated features and targeted nasal examination help distinguish overlapping conditions.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Early uncomplicated illnessSupport recovery without antibioticsFirst stepSymptoms have lasted around ten days or less without significant systemic illness.

1Explain the expected course and offer suitable analgesia with attention to individual contraindications.
2Saline may be tried for comfort, while explaining that evidence for symptom relief in acute sinusitis is limited.
3Do not routinely prescribe antibiotics, and avoid presenting steam inhalation or oral decongestants as established treatments.
4Advise reassessment for rapid worsening, systemic illness, failure to improve by three weeks or any eye or neurological warning feature.

02Persistent uncomplicated illnessChoose treatment after ten daysSymptoms have persisted for at least ten days without improvement.

1Consider a fourteen-day high-dose nasal corticosteroid course for patients aged twelve or over, discussing modest symptom benefit and off-label use.
2Discuss no antibiotic versus a back-up prescription according to clinical severity, likely bacterial features and individual complication risk.
3If providing a back-up prescription, explain use when symptoms fail to improve within seven further days or worsen significantly at any time.
4AlternativeReview a deteriorating patient for alternative diagnoses, resistance or a complication rather than simply extending the original course.

03Systemic illnessEscalate according to illness severityEscalationThe patient is systemically very unwell or at high risk of complications.

1Provide an immediate appropriate antibiotic when community management remains safe after assessment.
2Refer hospital red flags urgently, communicating visual findings, neurological symptoms, immune status and treatment already given.
3If symptoms worsen despite at least two to three days of a first-choice antibiotic, reassess and use the NICE second-choice pathway when appropriate.
4Seek microbiology advice if co-amoxiclav was already used or a suitable second-choice option is uncertain because of allergy.

04Chronic diseaseTreat persistent inflammation and reassessA compatible symptom cluster has continued for twelve weeks or longer.

1Check intranasal corticosteroid use and technique, offer suitable saline irrigation and address associated rhinitis and asthma.
2Refer persistent symptoms for confirmation of diagnosis, polyp assessment and consideration of specialist treatment.
3Investigate unilateral or atypical features and possible dental disease before calling symptoms treatment-resistant chronic rhinosinusitis.
4Use shared decisions about surgery or other specialist therapies after documenting functional burden and response to appropriate medical treatment.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

NICE first-choice oral antibiotic for selected uncomplicated acute sinusitis.

Phenoxymethylpenicillin for uncomplicated acute sinusitis when antibiotics are indicated

For adults aged eighteen or over, give 500 mg orally four times daily for five days, following NICE NG79 when an antibiotic is appropriate.

Check true penicillin allergy, renal impairment and the ability to take oral treatment. Gastrointestinal adverse effects and antibiotic-associated diarrhoea should be discussed; a prescription does not replace urgent referral for eye or neurological complications.

Broader oral option when the NICE severity or reassessment criteria apply.

Co-amoxiclav for higher-risk or second-choice treatment

For adults, give 500/125 mg orally three times daily for five days. NICE selects it initially for systemic illness or high complication risk, or after deterioration on a first-choice antibiotic for at least two to three days.

Avoid with penicillin hypersensitivity or previous co-amoxiclav-associated jaundice or hepatic dysfunction. Adjust for renal function where required, assess hepatic disease and review gastrointestinal toxicity; hospital complications need an inpatient plan.

NICE alternative when penicillin cannot be used and pregnancy is excluded.

Doxycycline for appropriate adults with penicillin allergy

Give 200 mg orally on the first day, followed by 100 mg once daily for four more days, making a five-day course for acute sinusitis.

Do not select this regimen in pregnancy; doxycycline is contraindicated below twelve years. Counsel on photosensitivity and oesophageal irritation, taking with adequate water and remaining upright; separate interacting iron, calcium or antacid preparations.

An option from age twelve after ten days of symptoms without improvement.

High-dose intranasal mometasone for prolonged acute symptoms

NICE studied 200 micrograms intranasally twice daily for fourteen days. With a 50-microgram-per-spray device, this is two sprays into each nostril twice daily, giving 400 micrograms daily; this acute sinusitis use is off-label.

Benefit is mainly symptom relief rather than shorter illness. Review concurrent corticosteroids, interacting CYP3A inhibitors, nasal infection, unhealed trauma or surgery and local bleeding. This is a defined acute course, not automatic indefinite high-dose treatment.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Orbital infection

Spread around or behind the orbital septum may progress to a collection and threaten vision. Eye movement pain, proptosis or visual change requires urgent hospital assessment.

Intracranial infection

Meningitis, empyema or brain abscess can follow sinus infection and may present with severe headache, neurological change or altered consciousness. These require coordinated emergency specialist care.

Persistent functional impairment

Chronic obstruction and smell loss can impair sleep, eating, safety awareness and wellbeing. Monitoring these consequences helps determine whether medical treatment or specialist escalation is achieving useful control.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Give the patient a clear expected recovery window and the specific deterioration threshold that changes the plan.
For back-up prescriptions, record when the prescription should be started and how to obtain reassessment if illness worsens.
Review antibiotic adverse effects and persistent symptoms after treatment rather than reflexively issuing another course.
In chronic disease, track smell, obstruction, sleep and a validated symptom measure such as SNOT-22 where used by the treating service.
After specialist intervention, continue the agreed topical regimen and scheduled follow-up because surgery does not remove the inflammatory tendency.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Green discharge has limitations

Discoloured mucus occurs during viral inflammation as well as bacterial infection. NICE uses the whole symptom pattern, duration and severity to inform management rather than treating mucus colour as an antibiotic test.

Penicillin allergy and pregnancy

When a macrolide is required in a pregnant adult with true penicillin allergy, NICE prefers erythromycin after benefit-risk assessment. The listed course is 250–500 mg four times daily or 500–1000 mg twice daily for five days, with interaction and tolerability review.

Another oral alternative

For a non-pregnant adult with penicillin allergy or intolerance, NICE also lists clarithromycin 500 mg orally twice daily for five days. Check QT risk, interacting medicines and renal or hepatic modifiers before choosing between alternatives.

Saline and symptom expectations

A rinse can help clear thick secretions but is not a substitute for drainage of an abscess or treatment of orbital infection. Use appropriately prepared water and a clean device, and avoid hot steam because it adds a burn risk without established benefit.

11Common pitfallsFrequent interpretation and management errors.

01
Prescribing antibiotics solely because nasal discharge has become green during the first week of a cold.
02
Using the fourteen-day high-dose nasal steroid course without explaining off-label acute use or reviewing other corticosteroids.
03
Repeating antibiotics for months of obstruction and anosmia without examining for polyps or confirming chronic disease.
04
Waiting for a routine outpatient scan when sinus symptoms are accompanied by impaired vision or neurological signs.