creation date: 2026-05-04 18:48
tags: Pathologies
Acute Rhinosinusitis
Background
Definitions
Acute rhinosinusitis (ARS) refers to the inflammation of the nasal cavity and paranasal sinuses.
The term sinusitis is not preferred as the inflammation of the sinuses rarely occurred without concurrent inflammation of the nasal mucosa.
Acute rhinosinusitis: symptoms <4 weeks
Subacute rhinosinusitis: symptoms 4-12 weeks
Chronic rhinosinusitis: symptoms >12 weeks
Recurrent acute rhinosinusitis: ≥4 episodes of ARS
Acute viral rhinosinusitis (AVRS): ARS with viral etiology
Uncomplicated acute bacterial rhinosinusitis (ABRS): ARS with bacterial etiology without clinical evidence of extension outside the paranasal sinuses and nasal cavity
Complicated ABRS: ARBS with clinical evidence of extension outside sinuses and nasal cavity
Etiology and Pathogenesis
Majority of cases are viral in origin. Common viruses are:
- Rhinovirus
- Influenza virus
- Parainfluenza virus
Inoculation begins with direct contact of virus to conjunctiva or nasal mucosa followed by replication. Symptoms develop within the first day with viral levels detectable in nasal secretions within 8-10 hours. Viral rhinitis spreads to the paranasal sinuses by systemic or direct routes, which may involve nose blowing.
Inflammation occurs due to sinonasal hypersecretion and increased vascular permeability, and through direct toxic effect from the virus.
Bacterial infection occur in only 0.5-2% of cases and often secondary to an inflamed sinus cavity caused by viral infection. Common bacteria, with the first two accounting for 75% of cases, are:
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
In the case of ABRS secondary to dental root infection, microaerophilic and anaerobic bacteria may be identified.
Clinical Presentation
Signs & Symptoms
Symptoms of ARS include:
- Nasal congestion and obstruction
- Purulent nasal discharge
- Maxillary tooth discomfort
- Facial pain or pressure that is worse or localized to the sinuses when bending forward
Other nonspecific symptoms include:
- Fever
- Fatigue
- Cough
- Hyposmia or anosmia
- Ear pressure or fullness
- Headache
- Halitosis
In cases of AVRS, partial or complete resolution of symptoms occur within 7-10 days with peak severity between day 3-6.
In cases of ABRS, symptoms tend to last longer (>10 days) and follow a “double worsening” pattern.
Physical findings include:
- Erythema or edema over involved cheekbone or periorbital area
- Cheek tenderness
- Purulent draining within the nose or posterior pharynx
- Mucosal edema may be appreciated on anterior rhinoscopy
History & Physical Exam
Physical exam should include rhinoscopy and otoscopy (especially if there are complaints of ear pain, fullness, or other auditory symptoms).
Risk Factors
Risk factors include:
- Older age (highest incidence among aged 45-64)
- Smoking
- Air travel
- Exposure to changes in atmospheric pressure
- Swimming
- Asthma and allergies
- Dental disease
- Immunodeficiency
Diagnosis
Criteria
Diagnosis of uncomplicated ARS is made clinically if both of the following are present:
- <4 weeks of purulent nasal drainage
- Severe nasal obstruction, facial pain/pressure/fullness, or both
Acute viral rhinosinusitis is diagnosed when:
- Patients have <10 days of symptoms
- Symptoms are not worsening
Acute bacterial rhinosinusitis is diagnosed with one of the following:
- Persistent symptoms or signs lasting ≥10 days without evidence of improvement
- Biphasic pattern of illness (double worsening) extending over a 10 day period
Work-up
Imaging
CT and XR are not indicated for clinically diagnosed uncomplicated rhinosinusitis. However, they are indicated if there is suspicion of spread beyond paranasal sinuses and nasal cavity.
- CT or MRI without and with contrast of head including paranasal sinuses; CT better for bone erosion, MRI for abscesses and inflamed tissue
Microbiologic testing
In patients suspected of serious complications, it is reasonable to use sinus aspirate or endoscopic cultures. This is performed by an ENT.
Differential
Other diagnoses include:
- Acute invasive fungal rhinosinusitis
- Common cold
Red Flags / Complications
The following red flags require urgent evaluation in the ED:
- Severe and persistent headache
- Periorbital edema, inflammation, or erythema
- Vision changes (double vision or impaired vision)
- Abnormal extraocular movements
- Proptosis
- Pain with eye movement
- Cranial nerve palsies
- Altered mental status
- Neck stiffness or other meningeal signs
- Papilledema or other sign of increased intracranial pressure
Complications of ABRS are rare but occur when infection spreads beyond the paranasal sinuses and nasal cavity and into the CNS, orbit, or surrounding tissue.
- Preseptal (periorbital) cellulitis - ocular pain, eyelid swelling and erythema
- Orbital cellulitis - ocular pain, eyelid swelling and erythema, pain with eye movements, proptosis, diplopia
- Subperiosteal abscess - similar to orbital cellulitis but with marked displacement of globe
- Osteomyelitis of sinus bones - gradual onset of dull pain, local findings, and systemic symptoms
- Meningitis - fevers, nuchal rigidity, change in mental status
- Intracranial abscess - headache, fever, neck stiffness, change in mental status, vomiting
- Septic cavernous sinus thrombosis
Management
The following management is for uncomplicated ARS. In cases where red flags are present, further evaluation will guide treatment.
Initial Symptom Management
For all patients, symptomatic management is the mainstay treatment, especially as most cases are viral and are self-limited regardless of viral or bacterial etiology.
Analgesics and antipyretics for fever and pain:
- Acetaminophen
- NSAIDs
Saline nasal irrigation is recommended to reduce need of pain medications. Note that irrigants should be prepared from sterile or bottled water.
Intranasal glucocorticoids are not routinely used except in some cases of patients with concomitant allergic rhinitis. Systemic glucocorticoids are not indicated.
Note that routine use of intranasal decongestants is not recommended except for a subjective sense of improved nasal patency. Long-term use may also cause rhinitis medicamentosa (severe rebound congestion) - they should not be used for >3 consecutive days.
Anti-Bacterial Therapy
For ABRS, antibiotics therapy may be indicated.
As ABRS is self-limited, an initial 7-day observation period is recommended (ie. start antibiotics at 17 day from onset, as 10 days is required for diagnosis). Earlier initiation of antibiotics may be indicated if:
- Immunocompromised or comorbidities affecting immune function
- Multiple comorbidities
- Unreliable/uncertain follow-up
- Known anatomic abnormalities that could predispose spread to eyes/brain
- Younger age (late teens to early 20s)
Instructions for return to clinic/ED or a delayed prescription can be used. Options include:
- Amoxicillin 500 mg PO TID or 875 mg BID
- Amoxicillin-clavulanate 500mg/125mg PO TID
- Doxycycline 100 mg PO BID or 200 mg daily (if allergic to penicillins)
For patients at risk of resistant pneumococcus (age ≥65, hospitalization/antibiotic use in last 3 months, immunocompromised status), high dose amoxi-clav (2g/125 mg XR tabs PO BID) is recommended.