Acute bacterial rhinosinusitis in children: Clinical features and diagnosis

INTRODUCTION — Acute rhinosinusitis is an illness that results from infection of one or more of the paranasal sinuses. A viral infection associated with the common cold is the most frequent etiology of acute rhinosinusitis, more properly called viral rhinosinusitis. (See "The common cold in children: Clinical features and diagnosis" and "The common cold in children: Management and prevention".)

Uncomplicated viral rhinosinusitis usually resolves without treatment in 7 to 10 days. Although acute bacterial rhinosinusitis (ABRS) also may resolve without treatment, treatment with antibiotics hastens recovery [1,2]. It is important to distinguish between uncomplicated viral rhinosinusitis and ABRS to prevent unnecessary use of antibiotics (table 1).

The clinical features and diagnosis of ABRS in children will be discussed here. The microbiology and treatment of ABRS in children and acute sinusitis and rhinosinusitis in adults are discussed separately. (See "Acute bacterial rhinosinusitis in children: Microbiology and management" and "Acute sinusitis and rhinosinusitis in adults: Clinical manifestations and diagnosis" and "Uncomplicated acute sinusitis and rhinosinusitis in adults: Treatment".)

ANATOMY — The paranasal sinuses develop as outpouchings of the nasal cavity (figure 1) [3]. The onset and duration of development of the paranasal sinuses vary with anatomic location, as described below. In most people, the nasal cavity and paranasal sinuses reach near-adult proportions by age 12 years, though development may not be complete until age 20 [4].

●The maxillary sinuses are present at birth and expand rapidly by four years of age [4]. Ciliary activity is necessary for drainage of secretions from the maxillary sinus into the nose because the ostia are located high on the medial walls of the maxillary sinus [5].

●The ethmoid sinuses are present at birth; they are made up of a collection of tiny air cells, each with its own opening into the nose [4].

●The sphenoid sinuses begin to develop during the first two years of life, are typically pneumatized by age five years, and attain their permanent size by age 12 years [4].

●Development of the frontal sinuses is variable [3]. By age six to eight years, they can be distinguished radiographically from the ethmoid sinuses [5] but do not complete their development for another 8 to 10 years.

Between 1 and 4 percent of adults have agenesis of the frontal sinuses, 80 percent have bilateral frontal sinuses, and the remainder have unilateral frontal sinus hypoplasia [3].

DEFINITIONS

●Sinusitis/rhinosinusitis – Sinusitis is inflammation of the mucosal lining of one or more of the paranasal sinuses [3]. The terms "sinusitis" and "rhinosinusitis" often are used interchangeably because inflammation of the paranasal sinuses is almost always accompanied by inflammation of the nasal mucosa [6].

Inflammation of the sinuses is common during uncomplicated upper respiratory infections but usually resolves spontaneously.

●Acute bacterial rhinosinusitis (ABRS) – ABRS occurs when there is secondary bacterial infection of the sinuses.

ABRS has been classified according to duration and recurrence as follows [7]:

•Acute – Symptoms completely resolve in <30 days

•Subacute – Symptoms completely resolve in ≥30 and <90 days

•Recurrent acute – At least three episodes of <30 days' duration separated by intervals of ≥10 days without symptoms in a six-month period, or at least four such episodes in a 12-month period; individual episodes respond briskly to antibiotic therapy

●Chronic sinusitis – Chronic rhinosinusitis is defined by episodes of inflammation of the paranasal sinuses that last >90 days, during which patients have persistent symptoms (cough, rhinorrhea, nasal obstruction). Chronic rhinosinusitis may be related to noninfectious conditions such as allergy, cystic fibrosis, ciliary dyskinesia, gastroesophageal reflux, or exposure to environmental pollutants [8,9]. Chronic rhinosinusitis is discussed separately. (See "Chronic rhinosinusitis: Clinical manifestations, pathophysiology, and diagnosis" and "Microbiology and antibiotic management of chronic rhinosinusitis".)

EPIDEMIOLOGY — Acute bacterial rhinosinusitis (ABRS) is a common problem in children. It is estimated that approximately 6 to 9 percent of viral upper respiratory infections in children are complicated by the development of secondary ABRS [2,10-13].

In children, ABRS typically occurs at four to seven years of age, but it can occur at any age, even infancy (complications of ethmoid sinusitis occasionally are observed in infants). ABRS is less common in children younger than two years of age than in older children. Two factors contribute to the decreased prevalence of ABRS in younger children. First, in younger children, the viral antecedent infection predisposes to acute otitis media (AOM) and treatment of AOM with antibiotics prevents the viral infection from evolving to ABRS. Second, the sinus ostia are larger (relative to the body of the sinus) than in older children and therefore less likely to be obstructed.

PATHOGENESIS — The paranasal sinuses are usually sterile [14-16]. However, they may be contaminated with bacteria that colonize the nasal mucosa and nasopharynx because the membranes that line the nose are continuous with the membranes that line the sinus cavities (figure 1).

The contaminating bacteria are typically removed by mucociliary clearance [3]. When mucociliary clearance is altered, the sinuses may be inoculated with large numbers of microorganisms, and infection may develop. Mucociliary clearance is altered by conditions that damage the ciliary epithelium or affect the number or function of cilia, the production or viscosity of mucous, or the patency of the ostia (eg, upper respiratory infections, allergic rhinitis) [17-19].

PREDISPOSING FACTORS — Viral upper respiratory infection (URI) is the most important risk factor for the development of acute bacterial rhinosinusitis (ABRS) [11,13,20]. The risk of viral URI is increased in children who attend day care [21]. In a longitudinal study of 237 children age 48 to 96 months who were followed for one year, children who developed ABRS had more frequent URIs than those who did not develop ABRS (three versus one per year) [13]. Respiratory syncytial virus was detected more often than other respiratory viruses in URIs that were complicated by sinusitis. The epidemiology and clinical manifestations of viral URI are discussed separately. (See "The common cold in children: Clinical features and diagnosis" and "Epidemiology, clinical manifestations, and pathogenesis of rhinovirus infections".)

Allergic rhinitis is another important risk factor for ABRS [22-24]. The epidemiology and clinical manifestations of allergic rhinitis are discussed separately. (See "Allergic rhinitis: Clinical manifestations, epidemiology, and diagnosis".)

Less common predisposing factors to ABRS include [3]:

●Anatomic obstruction (eg, nasal septal deformities; craniofacial anomalies; adenoidal hypertrophy; cysts of the maxillary antrum; or nasal foreign bodies, masses, or polyps).

Nasal polyps should prompt evaluation for possible cystic fibrosis and allergic diatheses [9]. (See "Etiologies of nasal obstruction: An overview" and "Cystic fibrosis: Clinical manifestations and diagnosis", section on 'Sinus and nasopharyngeal disease' and "Chronic rhinosinusitis: Clinical manifestations, pathophysiology, and diagnosis", section on 'CRS with nasal polyposis'.)

●Mucosal irritants (eg, dry air, tobacco smoke, chlorinated water).

●Sudden changes in atmospheric pressure (eg, descent in an airplane) [18].

CLINICAL FEATURES — The clinical manifestations of acute bacterial rhinosinusitis (ABRS) in children are similar to those of viral upper respiratory infection (URI) [25]. The clinical course, particularly the persistence and severity of symptoms, helps to differentiate between uncomplicated viral URI and ABRS [6,7,11,26]. (See 'Clinical course' below.)

Information correlating the clinical features of ABRS with microbiology is limited. Sinus aspiration is an invasive procedure that is not routinely performed in children with uncomplicated ABRS. (See "Acute bacterial rhinosinusitis in children: Microbiology and management", section on 'Microbiology'.)

Cough — Cough (wet or dry) is an important symptom in ABRS. In an observational study, 24 of 30 children with culture-confirmed maxillary ABRS had cough; it was the chief complaint in eight [26].

The cough becomes more prominent with increasing duration of illness [3]. The cough must be present during the day but is often described as worse at night [6,7]. Nocturnal cough as a single persistent symptom is nonspecific and more suggestive of postnasal drip or reactive airways disease [27].

Nasal symptoms — Nasal symptoms of ABRS include anterior or postnasal discharge, obstruction, and/or congestion. In an observational study, 23 of 30 children with culture-confirmed maxillary ABRS had nasal symptoms; nasal symptoms were the chief complaint in 10 [26].

The nasal discharge may be of any quality: watery, serous, or purulent. Postnasal discharge may cause vomiting, although posttussive emesis is more common.

On examination, there may be mild erythema and swelling of the nasal turbinates with mucopurulent anterior nasal discharge. Drainage from the posterior ethmoids may lead to purulent material in the posterior pharynx.

Fever — Fever is a variable symptom of ABRS and may occur in association with complications. In an observational study, 19 of 30 children with culture-confirmed maxillary ABRS had fever, but fever was not a chief complaint [26].

Temperature ≥39°C (102.2°F) for at least three consecutive days is a component of the severe presentation of ABRS. Fever that occurs in uncomplicated viral URI usually occurs early in the illness and resolves after two days (figure 2) [28]. (See 'Acute bacterial rhinosinusitis' below.)

Other findings — Complaints of headache and facial pain are also variable; they are less common in young children [26,29]. Sinus tenderness (rare in young children) may be elicited with percussion of the upper molars or percussion or application of direct pressure over the body of the frontal or maxillary sinuses [30,31].

Some children may complain of sore throat or have bad breath, but these are not usually the symptoms that lead to clinical presentation [26].

CLINICAL COURSE — Cough, nasal symptoms, and sore throat may occur with both uncomplicated viral upper respiratory infection (URI) and ABRS. The clinical course helps to differentiate the two clinical syndromes [6,7,26].

Uncomplicated upper respiratory infection — The course of most uncomplicated viral URIs is 7 to 10 days (figure 2) [11,28]. The patient may continue to have symptoms on the 10^th day but almost always the respiratory symptoms have begun to improve after peaking in severity on days three to six.

Most patients with uncomplicated viral URIs are afebrile. When fever occurs, it tends to do so early in the illness, with other constitutional symptoms (eg, headache, myalgias) [11,28,32]. The fever and constitutional symptoms typically resolve in the first 24 to 48 hours when the respiratory symptoms become more prominent.

The nasal discharge generally begins as clear and watery, but the quality may change during the course of illness. Most typically, the nasal discharge becomes thicker and more mucoid and may become purulent (thick, colored, and opaque) for several days, after which the changes reverse – the purulent discharge becomes more mucoid and then clear or simply dries up. The transition from clear to purulent to clear again occurs without antimicrobial therapy.

Acute bacterial rhinosinusitis — When viral URI is complicated by ABRS, there are three potential clinical presentations [6,7,26,33-35]:

●Persistent symptoms – The most common clinical presentation is onset with persistent symptoms [6,7,36]. The cardinal clinical features are nasal symptoms (anterior or posterior nasal discharge, obstruction, and/or congestion), cough, or both that persist for more than 10 but less than 30 days and are not improving [7]. Lack of improvement is extremely important. Some individuals with uncomplicated viral URI have residual respiratory symptoms at the 10-day mark. To be considered a sign of ABRS, these respiratory symptoms must be persistent without improvement.

The nasal discharge in patients with persistent symptoms may be of any quality: thick or thin, serous, mucoid, or purulent. The cough, which may be wet or dry, must be present during the daytime, although it is often described to be worse at night [6,7].

●Severe symptoms – ABRS can manifest with severe symptoms at onset. In children, this presentation is defined by a combination of temperature ≥39°C (102.2°F), concurrent purulent nasal discharge for at least three to four consecutive days, and ill-appearance [6,7]. Persistent high fever for at least three to four days distinguishes this presentation from an uncomplicated viral URI (in which fever is usually low-grade and present for less than 48 hours (figure 2) [28]).

●Worsening symptoms – ABRS also can present with worsening symptoms (ie, a biphasic illness or "double sickening") [33,37]. In this presentation, the initial illness is similar to an uncomplicated viral URI from which the patient seems to be recovering. However, on the sixth or seventh day, the patient becomes acutely and substantially worse with an increase in respiratory symptoms (exacerbation of nasal discharge or nasal congestion or daytime cough), a new onset of severe headache or fever, or a recurrence of fever if it had been present at the onset of illness.

Some children with persistent or worsening symptoms may actually have sequential viral URIs. In a longitudinal study, 237 children age 48 to 96 months were followed for one year and underwent nasal sampling at asymptomatic surveillance visits, on day 3 to 4 of URI and again if diagnosed to have ABRS (ie, day 10 of symptoms) [13]. In 9 of 31 (29 percent) episodes of ABRS, a different virus was detected on day 10 than on day 3. New viruses were more likely to be adenovirus, influenza, or respiratory syncytial virus and less likely to be rhinovirus.

COMPLICATIONS — Children with untreated bacterial rhinosinusitis are at risk for serious complications, which may be the presenting clinical manifestation (table 2). Complications may result from orbital or intracranial extension; orbital complications are most common. The exact rate of complications of ABRS is unknown, but they are estimated to occur in approximately 5 percent of patients hospitalized for rhinosinusitis [38,39].

Complications involving the orbit

Preseptal (periorbital) cellulitis — Preseptal cellulitis (inflammatory edema or sympathetic effusion) is a mild but common (the most common) complication of ABRS. It is characterized by swelling and erythema of the lids and periorbital area; there is no proptosis or limitation of eye movement [40]. Although the infection remains confined to the sinuses (usually the ethmoid sinuses), preseptal cellulitis indicates impediment to venous flow. Sinusitis complicated by preseptal cellulitis is more serious than sinus infections that occur without periorbital swelling.

Preseptal cellulitis is discussed in detail separately. (See "Preseptal cellulitis".)

Postseptal orbital complications — Postseptal complications of sinusitis that involve the orbit include orbital cellulitis, orbital subperiosteal abscess, and orbital abscess.

The characteristic clinical features of postseptal complications of sinusitis overlap and may include [38,40-42]:

●Periorbital swelling

●Erythema of the eyelid

●Pain with eye movement

●Conjunctival swelling (chemosis)

●Proptosis

●Limitation of eye movements (ophthalmoplegia)

●Diplopia

●Vision loss

When a postseptal complication of ABRS is suspected on the basis of clinical findings listed above, imaging is helpful in distinguishing between subperiosteal abscess, orbital abscess, and orbital cellulitis [43,44]. Subperiosteal abscesses and orbital abscesses appear as low-density collections on computed tomography (CT) scan. They often are located adjacent to the ethmoid sinus (figure 3). Subperiosteal abscesses occur between periosteum and the wall of the bony sinus (image 1).

●Orbital cellulitis – Orbital cellulitis is discussed in detail separately. (See "Orbital cellulitis".)

●Orbital subperiosteal abscess – Orbital subperiosteal abscess is the most common or second most-common postseptal complication of sinusitis in children [45-50]. In two single-institution, 10-year reviews of children hospitalized with orbital complications of ABRS, the prevalence of orbital subperiosteal abscess ranged from 9 to 23 percent [43,50].

Subperiosteal abscesses in younger children tend to occur medially in the orbit [51], to be amenable to antibiotic treatment without surgery (when small or in the form of poorly organized phlegmons) [51-53], and to contain a single aerobic species [53]. Abscesses in older patients may contain both aerobic and anaerobic microbes [54,55] and are more likely to require drainage than those in children. Nonmedial abscesses in older children, and abscesses located superiorly (near the frontal sinus), appear to be at highest risk to spread intracranially.

●Orbital abscess – Patients with orbital abscess typically have more severe signs (proptosis, ophthalmoplegia) and symptoms (pain with eye movements) than those without orbital abscess [43,44].

In a retrospective cohort study that included 298 otherwise healthy children admitted to a pediatric emergency department who underwent CT scanning for suspected acute periorbital (preseptal) or orbital cellulitis, six (2 percent) were found to have an orbital abscess [44]. Proptosis, pain with external ocular movement, and ophthalmoplegia were associated with the presence of an orbital abscess, although 51 percent of patients with abscess did not have these findings. On multivariate analysis, other factors associated with orbital abscess were a peripheral absolute neutrophil count >10,000 per microL, absence of conjunctivitis, periorbital edema, age >3 years, and previous antibiotic therapy. (See "Orbital cellulitis", section on 'Imaging studies'.)

Intracranial complications — Frontal and sphenoidal sinusitis are the most likely to lead to intracranial complications, which may require surgical intervention and lead to permanent neurologic disability and rarely death; headache is a prominent symptom in these patients [56,57].

Findings that should prompt consideration of intracranial extension include [52,58,59]:

●The combination of eye swelling with persistent headache and vomiting

●Vomiting and headache that requires hospital admission, particularly in older children

●Vomiting that persists for more than 24 hours

●Altered level of consciousness

●Focal neurologic deficits

●Signs of meningeal irritation (eg, stiff neck)

In a retrospective case-series of 54 children hospitalized for surgical management of intracranial complications of ABRS, 25 had abnormal neurologic examination at the time of admission, but 18 had neither neurologic symptoms nor vomiting [59]. Nearly all patients (89 percent) reported a median of two health care visits before admission. Epidural abscess and subdural empyema were the most common complications.

Clinical manifestations specific for intracranial complications of rhinosinusitis are listed below (table 2) [60-64]:

●Septic cavernous sinus thrombosis – Bilateral ptosis, proptosis, ophthalmoplegia, bilateral periorbital edema, headache, change in mental status. (See "Septic dural sinus thrombosis".)

●Meningitis – Fever, headache, nuchal rigidity, change in mental status. (See "Bacterial meningitis in children older than one month: Clinical features and diagnosis", section on 'Clinical features'.)

●Osteomyelitis of the frontal bone associated with a subperiosteal abscess (Pott puffy tumor (image 2)) – Forehead or scalp swelling and tenderness, headache, photophobia, fever, vomiting, lethargy [65].

●Epidural abscess – Papilledema, focal neurologic signs, headache, lethargy, nausea, vomiting. (See "Intracranial epidural abscess".)

●Subdural abscess – Fever, severe headache, meningeal irritation, progressive neurologic deficits, seizures, signs of increased intracranial pressure (papilledema, vomiting) [66].

●Brain abscess – Headache, neck stiffness, changes in mental status, vomiting, focal neurologic deficits, seizures, third and sixth cranial nerve deficits, papilledema. (See "Pathogenesis, clinical manifestations, and diagnosis of brain abscess".)

RADIOLOGIC FEATURES — Imaging studies are not usually necessary in the evaluation of children with uncomplicated acute bacterial rhinosinusitis. When imaging studies are obtained, abnormal findings should be interpreted in the context of clinical findings [67,68].

Radiographic or CT findings that are compatible with sinus inflammation include (image 3) [9,69]:

●Complete opacification

●Mucosal thickening of at least 4 mm

●Air-fluid level

However, abnormal imaging studies cannot distinguish between bacterial, viral, or other causes of sinus inflammation [6,70]. Observational studies performed with radiographs, CT, and magnetic resonance imaging have demonstrated frequent abnormalities in the paranasal sinuses of children [67,71-73] and adults with uncomplicated viral upper respiratory infection [74].

Normal imaging studies (CT or radiograph) of the paranasal sinuses in children with respiratory symptoms excludes rhinosinusitis as the cause of the symptoms.

DIAGNOSIS

Uncomplicated ABRS — The diagnosis of uncomplicated acute bacterial rhinosinusitis (ABRS) in children is usually made clinically. Imaging studies are not recommended for the diagnosis of uncomplicated ABRS [7].

We use both of the following criteria for diagnosis [6,7,26,33-35]:

●Symptoms and signs compatible with sinus inflammation (daytime cough, nasal symptoms, or both) (see 'Clinical features' above), and

●Clinical course suggestive of bacterial rather than viral infection, including (see 'Acute bacterial rhinosinusitis' above):

•Symptoms present without improvement for >10 and <30 days, or

•Severe symptoms (ill appearance, temperature ≥39°C (102.2°F), and purulent nasal discharge for ≥3 consecutive days), or

•Worsening symptoms (increase in respiratory symptoms, new onset of severe headache or fever, or recurrence of fever after initial improvement)

We have chosen these relatively strict criteria to limit the diagnosis to patients most likely to benefit from antimicrobial therapy [6]. These criteria agree with those of a multidisciplinary consensus panel and clinical guidelines developed by the American Academy of Pediatrics and the Infectious Diseases Society of America [6,7,34,35]. They are supported by a study in which 77 percent of sinus aspirate cultures in children with persistent or severe symptoms grew ≥10⁴ colony forming units of pathogenic bacteria [26]. However, in approximately one-third of episodes of ABRS according to these criteria, sequential viral infections may be responsible for symptoms [13].

Complicated ABRS — Imaging studies are usually performed in children suspected to have orbital and intracranial complications of ABRS (table 2) [7,27]. (See 'Complications' above.)

For children with potential orbital or intracranial complications of ABRS, we obtain contrast-enhanced CT imaging of the orbits, sinuses, and brain [6,7,70]. Magnetic resonance imaging (MRI) is an alternative. Advantages of CT include increased availability, lack of need for sedation, and better demonstration of the sinus anatomy including the ostiomeatal complex and bony structures [6]. Advantages of MRI include improved ability to detect intracranial complications without exposure to radiation [75-77].

Microbiologic evaluation — Microbiologic evaluation usually is not necessary for children with uncomplicated ABRS who improve as expected with antimicrobial therapy. (See "Acute bacterial rhinosinusitis in children: Microbiology and management".)

●Indications – We attempt to identify the pathogen in children with ABRS who [6]:

•Are toxic appearing (eg, lethargic, poorly perfused, cardiorespiratory compromise)

•Have orbital or intracranial complications

•Are immunocompromised

•Have recurrent ABRS

•Fail to respond to antimicrobial therapy

Isolation of a pathogen and antimicrobial susceptibilities permit better targeting of antimicrobial therapy.

●Preferred procedure – When identification of a pathogen is necessary in children, sinus aspiration is the preferred method for obtaining samples (figure 4); children with ABRS are rarely bacteremic [6,78].

Sinus aspiration should be performed by a specialist [6]. Appropriate sterilization of the area of the nose through which the trocar will pass is essential to avoid contamination from the nasal cavity [79].

●Microbiologic studies – Aspirated fluid should be sent for Gram stain, aerobic and anaerobic culture, and antimicrobial susceptibility testing. Sinus aspiration with a culture that yields ≥10⁴ colony-forming units/mL of a significant pathogen is the reference standard for diagnosis of ABRS [6,33,80,81].

●Procedures that are not recommended – Nasopharyngeal, nasal, and/or throat cultures should not be used as a surrogate for sinus aspiration in children with suspected ABRS. There is a poor correlation between nasopharyngeal and throat cultures and bacteria isolated from sinus aspirates [26]. There is also poor correlation between negative nasopharyngeal cultures and absence of sinus disease (as documented by normal sinus radiographs) [82]. (See 'Radiologic features' above.)

Although there is literature suggesting that endoscopically obtained cultures of the middle meatus may be a surrogate for sinus aspiration, endoscopically obtained cultures of the middle meatus are of no use in children suspected to have ABRS because the meatus is colonized with Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, even when children are asymptomatic [83].

DIFFERENTIAL DIAGNOSIS — The main consideration in the differential diagnosis of acute bacterial rhinosinusitis is the distinction between viral upper respiratory infection and secondary bacterial infection of the paranasal sinuses (table 1). The clinical course, particularly the persistence and severity of illness, is helpful in making this distinction. (See 'Clinical course' above.)

Other possible diagnoses in children with persistent nasal symptoms and/or cough include (table 1) [3,9]:

●Allergic rhinitis with or without reactive airways disease. Children with allergic rhinitis may have "allergic facies" (eg, infraorbital edema, accented lines or folds below the lower eyelids, a transverse nasal crease) (figure 5) and/or "cobblestoning" of the posterior pharynx. (See "Allergic rhinitis: Clinical manifestations, epidemiology, and diagnosis", section on 'Clinical manifestations'.)

●Nasal foreign body (usually suspected on basis of foul odor and serosanguineous nasal drainage; may be apparent by direct observation). (See "Diagnosis and management of intranasal foreign bodies", section on 'Clinical manifestations'.)

●Infected adenoids (associated symptoms and signs include mouth breathing, halitosis, snoring, and downward displacement of the soft palate [adenoids are usually not seen during oropharyngeal examination]). (See "Etiologies of nasal obstruction: An overview", section on 'Enlarged adenoids'.)

●Gastroesophageal or laryngopharyngeal reflux disease may be associated with persistent nasal discharge, wheezing, and cough.

●Pertussis, particularly in the catarrhal stage. In pertussis, nasal symptoms usually resolve after one to two weeks, after which the severity of cough increases. The cough is typically paroxysmal and sometimes followed by an inspiratory whoop. Paroxysmal cough distinguishes pertussis from sinusitis. (See "Pertussis infection in infants and children: Clinical features and diagnosis", section on 'Classic presentation'.)

SOCIETY GUIDELINE LINKS — Links to society- and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Acute rhinosinusitis".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient education" and the keyword[s] of interest.)

●Basics topic (see "Patient education: Sinusitis in children (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Definitions – Rhinosinusitis is inflammation of the mucosal lining of one or more of the paranasal sinuses. Such inflammation is common during viral upper respiratory infections (URI) but usually resolves spontaneously. Acute bacterial rhinosinusitis (ABRS) occurs when there is secondary bacterial infection of the sinuses. (See 'Definitions' above.)

●Predisposing factors – Viral URI and allergic rhinitis are the most frequent predisposing factors for ABRS in children. Less common predisposing factors include anatomic obstruction, mucosal irritants, and sudden changes in atmospheric pressure. (See 'Predisposing factors' above.)

●Clinical features – The clinical features of ABRS include cough, nasal symptoms, fever, halitosis, headache, facial pain and swelling, and sore throat. (See 'Clinical features' above.)

The clinical course, particularly the persistence and severity of symptoms, helps to differentiate between ABRS and viral URI. (See 'Clinical course' above.)

●Complications – Children with ABRS are at risk for serious complications, which may be the presenting manifestation (table 2). Complications may result from orbital or intracranial extension. (See 'Complications' above.)

●Diagnosis

•Uncomplicated ABRS – The diagnosis of uncomplicated ABRS can be made clinically in children with symptoms and signs of sinus inflammation (ie, daytime cough, nasal symptoms, or both) and one of the following presentations (see 'Uncomplicated ABRS' above):

-Symptoms present without improvement for >10 and <30 days, or

-Severe symptoms (ie, ill appearance, temperature ≥39°C [102.2°F], and purulent nasal discharge for ≥3 consecutive days), or

-Worsening symptoms (ie, increase in respiratory symptoms, new onset of severe headache or fever, or recurrence of fever after initial improvement)

Imaging studies are not necessary for children with uncomplicated ABRS.

•Complicated ABRS – For children with potential orbital or intracranial complications of ABRS (table 2), we obtain contrast-enhanced CT imaging of the orbits, sinuses, and brain. Magnetic resonance imaging is an alternative. (See 'Complications' above and 'Radiologic features' above.)

●Differential diagnosis – The differential diagnosis of ABRS includes uncomplicated viral URI, allergic or nonallergic rhinitis, nasal foreign body, enlarged or infected adenoids, mucosal cyst of the maxillary antrum, and the catarrhal stage of pertussis (table 1). These conditions can usually be distinguished from ABRS with history and examination, but imaging may be necessary to exclude structural abnormalities. (See 'Differential diagnosis' above.)