Pediatric sinusitis

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU

Nasal physiology

Mucociliary clearance can be tested by placing saccharin on the inferior turbinate and timing the onset of sweet taste in the mouth. The normal range is 7-11 minutes.

There is normal asymmetry of nasal mucosa swelling, with one side of nose swollen as a result of dilatation of veins in the inferior turbinate and the other side "open" - 80% of the population exhibits a nasal cycle, with reciprocal changes in airflow over 1-2 hours.

Anatomy of paranasal sinuses

Sinus is a Latin word for “fold” or “pocket”. Paranasal sinuses have an embryogenic origin from the nasal passage and are an integral component of the airway. Drainage pathways of the sinuses are complex and can be blocked during inflammation. Ostia are the sinus openings in the nasal cavity. They are 2-6 mm wide.

Paranasal sinuses have an embryogenic origin from the nasal passage and are an integral component of the airway. Drainage pathways of the sinuses are complex and can be blocked during inflammation.

The outflow tract of the maxillary sinus is positioned high on medial wall, therefore intact mucociliary apparatus required to move mucus and debris from sinus into nose.

The ethmoid sinus consists of 3 to 15 air cells (on left and right sides), separated by thin bony partitions. Each air cell drains by tiny ostium into middle meatus and the ostia are easily obstructed during URI.

The frontal sinus develops from anterior ethmoid cell and achieves supraorbital position by 6 years of age. It is an uncommon site of infection in pediatrics.

The sinus ostia are the drainage routes for paranasal sinuses - because of their small diameter (1.0-2.5 mm), they are easily occluded by mucosal inflammation. This is is similar to the blockage of Eustachian tube that can lead to otitis media.

How large are the ostia of the sinuses?

The size of ostium of the maxillary sinus is 2.5 mm, the ostia of the other sinuses are smaller - in the range of 1 mm.

Location of the openings of the sinuses

- Inferior meatus - opening of nasolacrimal duct.
- Middle meatus - frontal, maxillary and anterior ethmoids
- Superior turbinate - posterior ethmoids and sphenoid sinuses


Sinuses listen to the following radio channels: FM AM / PS SS

Frontal sinus, Maxillary sinus, and
Anterior ethmoids drain into Middle meatus
Posterior ethmoids and Sphenoid sinus drain into
Sphenoethmoidal recess above Superior turbinate


Sinusitis of less than 4 weeks’ duration is considered acute. Chronic sinusitis persists for more than 4 weeks.

Recurrent sinusitis is defined as 4 or more episodes of sinusitis per year. Each episode lasting 7-10 days and no symptoms during intervening periods. Sinusitis is mostly preceded by rhinitis and is rarely found without rhinitis.

The 1997 Rhinosinusitis Task Force thus proposed the term Rhinosinusitis instead of Sinusitis (reiterated in 2007 guidelines).


The diagnosis is clinical most of the time.

Radiographic findings suggestive of acute sinusitis:

- diffuse opacification - most common finding in children with acute bacterial sinusitis
- mucosal swelling greater than 4 mm
- presence of air-fluid level - may not occur in children

Maxillary sinus aspiration recovered bacteria from 75% of children with abnormal radiographic findings (Wald et al, 1981).

History of persistent upper respiratory symptoms predicted abnormal findings on radiographs in 88% of children younger than 6 yr of age and in 70% of children older than 6 yr of age (Wald et al, 1986).

The frequency of bacterial sinusitis peaks by 6 years of age.

According to the current guidelines, the diagnosis of acute bacterial sinusitis does not require radiographic imaging in children younger than 6 yr of age with persistent upper respiratory symptoms. The diagnosis is based on clinical findings only. There is no consensus about the need for imaging for children older than 6 yr of age with persistent symptoms and for all children with severe or worsening symptoms.

Do you need an X-ray to diagnose sinusitis in children?

Acute sinusitis in children is likely if the symptoms persist for tnan 10 but less than 30 days and they are not improing. This predicts abnormal X-ray in 88% of children yonger than 6 years. They can be treated with an antibiotic withouth an X-ray.

The "story" is different in children older than 6 years - 30% of them had a normal X-ray and this group may not need an antibiotic. Only 75% of children with abnormal X-rays had a positive bacterial sinus aspirate.

Sinus Imaging for Diagnosis of CRS in Children - plain radiography has limited utility - CT and MRI have a major role (

Pathogens in pediatric sinusitis

From aspiration of maxillary sinus ((Wald et al, 1981):

- Streptococcus pneumoniae, 30% to 40%
- Haemophilus influenzae, 20%
- Moraxella catarrhalis, 20%
- Streptococcus pyogenes (group A streptococci), 4%
- no bacteria recovered from 25% of samples

The widespread use of pneumococcal vaccine has resulted in changes in prevalence. The recent data is from tympanocentesis studies of children with acute otitis media and showed decreased rate of infection with S pneumoniae and increased rate of infection with H influenzae. The data can be extrapolated to sinusitis - some ENTs consider the middle ear "a paranasal sinus."

Antibiotic resistance

- 35% of isolates of H influenzae and 100% of isolates of M catarrhalis are resistant to b-lactam antibiotics
- 25% to 50% of isolates of S pneumoniae resistant to penicillin (half are highly resistant)

"Plain old" amoxicillin will not help in those cases.

Treatment of Acute Sinusitis

Recommendations form the current guidelines

For children with uncomplicated mild to moderate acute bacterial sinusitis without risk factors (age less than 2 yr; recent use of antibiotics; attendance at daycare), give amoxicillin or amoxicillin-clavulanate, 45 to 90 mg/kg per day (in 2 divided doses).

In acute sinusitis in children, you often have to use high dose amoxicillin (90 mg per kg) - 45 mg per kg is not helful because of resistance.

In penicillin allergy, you can use cefdinir, cefuroxime, or cefpodoxime for children with mild allergy; clarithromycin or azithromycin for children with type-1 hypersensitivity (but these have low activity against Haemophilus).

If there is no effect within 72 hr, consider increasing dose of amoxicillin-clavulanate to 80 to 90 mg/kg per day (2 divided doses).

Amoxicillin-clavulanate to 80 to 90 mg/kg per day should be used in:

- patients who do not improve within 72 hr
- those who have recently received antibiotics
- moderate to severe disease

These higher doses achieve concentration needed to eradicate most highly-resistant S. pneumoniae

How long should you treat with an antibiotic?

The minimum ciurse is 10 days. A simple rule is to treat until the patient becomes symptom free plus 7 more days.

When to change the antibiotic?

If children are treated with an antibiotic, they should start to get better within 48 hours, and should feel substantially better within 72 hours. If they do not feel better within 72 hours (3 days), you either got the wrong diagnosis or the wrong antibiotic. It is reasonable to start with amoxicillin/clavunate, and if there is no effect within 72 hours, switch to cefpodoxime.

What is the role of corticosteroids nose sprays?

Some studies show modest benefit of intranasal corticosteroids. Intranasal decongestants (eg, oxymetazoline form 3 days) or saline irrigation may be useful.


Pediatric sinusitis. Ellen R. Wald, MD. Audio-Digest Pediatrics, Volume 55, Issue 14, July 21, 2009.
Acute and Chronic Rhinosinusitis: Practical Clinical Treatment Strategies. Nancy Otto, PharmD. Medscape, 11/2008.
Sinusitis Practice Guideline Aims to Improve Diagnosis, Cut Antibiotic Use. AFP, 2007.
Antibiotic Treatment for Rhinosinusitis - Levofloxacin recommended for children with penicillin allergy? Medscape, 2012.

Related reading

FIT Corner Questions. Chapter 78 of the 6th edition of Middleton’s Allergy Principles and Practice, edited by N. Franklin Adkinson, et al. September 27, 2006. Chapter 78: Nasal Polyps and Sinusitis.
Unlike otitis media, visit rate for acute sinusitis among children did not decrease after pneumococcal conjugate vaccine, Pediatrics, 12/2010.
The best price for azithromycin is at Costco: 18 tablets for $18.
SNOT-16 Assessment Tool for Acute Sinusitis takes 5 minutes - copyright protected by Washington University. Medscape, 2011.
Intranasal Treatment for Clogged Ears: ears are connected to the back of the nose via a tunnel called Eustachian tube.
Mnemonics for sinusitis: PODS and C-PODS (end of PDF here)

Published: 05/29/2010
Updated: 03/30/2012

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