Making a definitive diagnosis for a pediatric patient presenting with
conjunctivitis can be difficult. Conjunctivitis in the pediatric patient can be
mimicked by nasolacrimal duct (NLD) obstruction and caused by allergies,
bacteria, and viruses. Because antimicrobial cultures take time and are not
always accurate, the diagnosis and treatment of conjunctivitis are often based
on the physician’s knowledge regarding the current literature on likely
pathogens and clinical experience. Therefore, pediatricians must be aware of
the clinical signs and symptoms that can provide a differential diagnosis of
conjunctivitis, so that it can be properly treated.
Pediatricians must be aware of the clinical signs and symptoms that can provide a differential diagnosis of conjunctivitis, so that it can be properly treated.
Nasolacrimal Duct Obstruction
— Rudolph S. Wagner, MD
NLD obstruction is always in the differential diagnosis for
conjunctivitis during the first year of life. Effort should be made to rule out
NLD obstruction as the cause of the patient’s symptoms. With NLD
obstruction, the child’s eyelids may be matted together or discharge may
be seen along the lashes or down the child’s cheek. However, patients with
NLD obstruction present with less conjunctival injection than patients with
bacterial conjunctivitis. Also, if the child’s face has been cleaned to
prepare the child to see the physician, signs will usually recur during the
A definitive diagnosis of NLD obstruction can be made by digital massage
of the lacrimal sac. When massaged, the nasolacrimal duct will produce a reflux
of mucous from the puncta. The fluorescein dye disappearance test is most
helpful when the condition is unilateral. After fluorescein dye has been
administered to each eye, the dye will take longer to clear from the eye with
Presentation of Allergic Conjunctivitis
The number of children presenting to the clinic with allergic
conjunctivitis will vary according to the season. Allergic conjunctivitis is
caused by an acute type I hypersensitivity to common allergens. Allergic
conjunctivitis has a protracted course, with the severity of symptoms waxing
and waning throughout the allergy season. This is another way to differentiate
allergic conjunctivitis from other forms, as recurrences within a short period
of time are unlikely with bacterial or viral conjunctivitis. Symptoms include
itchy eyes, watery or stringy discharge, chemosis, eyelid edema, rhinitis, and
an “allergic shiner.” Chemosis (swelling of the conjunctiva) can be
marked and may cause the cornea to appear as if it is sitting in a depression.
In addition to seasonal allergic conjunctivitis, there are vernal limbal or
palpebral types. With vernal limbal conjunctivitis, there is an accumulation of
eosinophils along the limbus; with vernal palpebral conjunctivitis, large
papules form under the conjunctiva of the upper eyelid.
Presentation of Viral Conjunctivitis
Viral conjunctivitis is more common in older children and adults than it
is in preschool-aged children. Viral conjunctivitis is highly contagious and is
characterized by watery discharge. The amount of vascular injection can be
variable. Viral conjunctivitis is usually caused by adenovirus, but can also be
caused by other viruses such as herpes simplex virus (HSV).
HSV may be one of the most problematic causes of conjunctivitis. This
virus can lead to herpetic keratitis and possibly loss of vision.
Corticosteroids, sometimes used as palliative care in cases of viral
conjunctivitis caused by other viruses, are contraindicated in conjunctivitis
caused by HSV. The disease is almost always unilateral and monocular. Patients
with herpetic conjunctivitis may complain of severe pain. The eyelids may also
be involved — they can be red, edematous, and display multiple vesicles.
The corneal reflex in a patient with herpetic conjunctivitis will be irregular,
not be sharp and crisp. Upon close examination, dendrites or small opacities
may be observed. Herpetic conjunctivitis should be in the differential whenever
a patient is not responding to antibiotic therapy. Patients with conjunctivitis
thought to be caused by HSV should always be referred to an ophthalmologist.
Acute hemorrhagic conjunctivitis (AHC) is most commonly caused by a
picornavirus, usually Coxsackie A24 or enterovirus 70. The presentation of AHC
is often dramatic. The eye will become acutely painful and possibly photophobic
even before hemorrhages can be seen. The subconjunctival hemorrhages that
characterize this disease begin as petechiae which then coalesce and can
involve the entire subconjunctiva. While highly contagious, AHC is
self-limiting and its complications are rare.
Presentation of Bacterial Conjunctivitis
Acute bacterial conjunctivitis is most frequently observed among
infants, toddlers, and preschool-aged children. One in 8 children has an
episode every year, and there are 5 million cases in the United States
annually. Bacterial conjunctivitis is a self-limiting disease, typically
lasting 7 to 10 days without antibiotic treatment.1-3
in 1 study 83% of children diagnosed with bacterial cconjunctivitis treated
with a vehicle washout drop containing no active medication had clinical cures
at 7 days.1
Viral conjunctivitis usually lasts longer than bacterial
conjunctivitis. If conjunctivitis does not resolve with antibiotics after 3 to
4 days, the physician should suspect that the infection is viral.
Bacterial conjunctivitis is characterized by mucopurulent discharge with
matting of the eyelids. Common clinical findings in acute bacterial
conjunctivitis include burning and stinging. While bacterial conjunctivitis can
present in only one eye, it is usually present in both eyes or will spread to
the contralateral eye. Acute bacterial conjunctivitis can be associated with
otitis media. When a patient presents with both conjunctivitis and otitis
media, systemic antibiotics are indicated.4,5
conjunctivitis, bacterial conjunctivitis is highly contagious.
Differentiating Bacterial from Viral Conjunctivitis
Bacterial conjunctivitis can be differentiated from viral conjunctivitis
based on discharge (mucopurulent vs. watery), age of the affected child
(preschool-aged vs. school-aged children), and whether the infection is
bilateral or unilateral (Table 1).
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Ocular Pathogens in Bacterial Conjunctivitis
Studies have shown that pediatric acute conjunctivitis is most often caused by
bacteria. Viruses and allergies are the second and third most common causes
The younger the patient, the higher
the likelihood of a bacterial etiology of the conjunctivitis.
Click here for larger version of this Figure.
A variety of studies have been performed to determine the organisms
responsible for conjunctivitis. In a study of 95 patients with acute
conjunctivitis and 91 control children of similar age, specimens of the lid and
conjunctiva were obtained for culture and conjunctival scrapings were stained
with Giemsa and Gram stains. Bacterial infections were identified in 80% of
patients, viral infections were identified in 13%, and allergies in 2%. No
cause could be determined in 5% of patients. Of the patients with bacterial
conjunctivitis, Haemophilus influenzae
accounted for 58.1% of all
bacterial cultures. Streptococcus pneumoniae
was the second most common
pathogen, accounting for 27.1% of bacteria cultures. Moraxella
was isolated from cultures in 8.1% of patients. Staphylococci
accounted for 4.1% of cultures and species included Staphylococcus
(2.7%) and other coagulase-negative staphylococci (1.4%).
Staphylococci, corynebacteria, and alpha-hemolytic streptococci were the
predominant organisms recovered from the lids of control subjects.6
In a prospective study in a children’s hospital emergency
department published in 2007, conjunctival swabs were obtained for bacterial
culture from 111 patients aged 1 month to 18 years (mean age, 33 months) who
presented with red or pink eye and/or the diagnosis of conjunctivitis.
Bacterial cultures were positive in 78.4% of the patients tested. Nontypeable
accounted for 82% of positive cultures, S pneumoniae
for 16%, and Staphylococcus aureus
The decrease in
the proportion of isolates positive for S pneumoniae
compared to the
study published in 1993 may be due to pneumococcal conjugate vaccine
A prospective observational cohort study at an urban pediatric emergency
department was published in 2010. Conjunctival swabs were taken from children
aged 6 months to 17 years who presented with conjunctival erythema, eye
discharge, or both. The median age was 3 years. Patients were excluded from the
study if they had a history of ocular trauma, were exposed to a noxious
chemical, wore contact lenses, or had used antibiotics in the previous 5 days.
Bacterial cultures were isolated from 64.7% of the 368 patients enrolled in the
study. H influenzae
accounted for 67.6% of positive cultures, S
for 19.7%, and S aureus
for 8.0% (Figure 2).8
Click here for larger version of this Figure.
This study also investigated how it could be determined that
conjunctivitis is not likely to be of bacterial etiology. They determined 4
factors that were likely to be associated with cultures that were negative for
- > 6 years of age
- Presentation in April through November
- Watery or no discharge
- No glued eye in the morning
In this study, 92.2% of patients with all of these factors had cultures
that were negative for bacteria and 76.4% of those with 3 factors had negative
cultures. These data can aid a physician in deciding whether or how to treat a
patient in some cases.
While the data in these 3 studies are consistent and compelling,
physicians must also remember that atypical outbreaks of bacterial
conjunctivitis can occur. Two notable outbreaks of bacterial conjunctivitis
have been caused by an atypical strain of S pneumoniae
The outbreak at Dartmouth College in New Hampshire in 2002 is especially
significant because outbreaks of conjunctivitis in college-aged students are
usually viral in etiology. From January 1 through February 15, 197 students
were diagnosed with conjunctivitis. A viral cause was initially suspected, but
conjunctival swabs from 12 students grew S pneumoniae
. Because of the
high number of cases and the unusual bacterial etiology in college-aged
students, an investigation was initiated. Specimens were sent to the
Dartmouth-Hitchcock Medical Center for culture and identification. Subcultures
of presumed S pneumoniae
isolates were then sent to the CDC for further
Results of the investigation demonstrated that between January 1, 2002 and April 12, 2002, 698 of the 5,060 students enrolled at Dartmouth College
were diagnosed with conjunctivitis. During similar periods in 2000 and 2001,
only 66 and 92 students, respectively, were diagnosed with conjunctivitis.
During the 2002 outbreak, 34 students suffered repeated infections as defined
by visits to the health center for conjunctivitis by the same student that
occurred more than 14 days apart. The attack ratio among the 3,682
undergraduates and 1,378 graduate students was 18.7% and 2.5%, respectively. Of
the positive cultures, 43.3% grew nonencapsulated pneumococci.9
outbreak exemplifies that bacterial conjunctivitis can occur in young adults
and conjunctivitis should not be assumed to be due to adenovirus in this age
Nontypeable pneumococcus also caused an outbreak of bacterial
conjunctivitis in Westbrook, Maine later in 2002. From September 20 to December
6, at the index elementary school, a total of 101 students (out of 361) had at
least 1 episode of conjunctivitis. Eleven of 20 students tested (55%) had an
episode of culture-confirmed pneumococcal conjunctivitis. Additionally, school
nurses and child care staff in the community reported an additional 4% of
students attending kindergarten through grade 12 at 4 schools, and 9% of
children attending 3 community child care centers, having conjunctivitis during
this time period.
Among the 53 students with conjunctivitis at other schools, 10 (19%) had
a family member at the index school, and seven (29%) of 24 ill child care
attendees had a sibling at the index school. Of 15 conjunctival specimens
collected from students at other schools, 5 (33%) grew S pneumoniae
CDC advises, “health care providers and public health officials should be
aware that nontypeable S pneumoniae
can cause outbreaks of
conjunctivitis in school-aged children and college students; outbreaks should
be reported to state health departments and the CDC.”10
Antibiotic Resistance and Bacterial Conjunctivitis
In a retrospective cross-sectional study, the microbiology records of
all patients (adults and children) with bacterial conjunctivitis seeking
treatment at Bascom Palmer Eye Institute in Miami from January 1, 1994 through
December 31, 2003 were reviewed. For an eye to have been included in the study,
conjunctival swabs must have resulted in a positive culture. Over this 10-year
period in South Florida, the most common isolate from the 2,408 consecutive
swabs was S aureus
(37.6%). Children < 7 years of age were most
likely to have gram-negative infections, most frequently H influenzae
but S aureus
was the second most common isolate in children younger than
6 years of age. Of the S aureus
isolates, 19.1% were resistant to
methicillin. The incidence of methicillin-resistant S aureus
increased over the decade. There were also 2-fold and 3-fold increases in
resistance of gram-positive organisms to erythromycin and
Nosocomial and community-acquired MRSA infections have also been
reported in children. Many neonatal intensive care units (NICUs) take weekly
pharyngeal swabs of every neonate to test for MRSA colonization. Neonates who
are colonized with MRSA may show no signs of infection but MRSA infections in
neonates are possible. In 1 report, a 7-day-old neonate was referred to the
ophthalmology team with a 1-day history of purulent conjunctivitis in the right
eye. The conjunctival swab taken before any antibiotics were administered grew
MRSA. Both parents were also found to be colonized by MRSA and likely
transmitted it to their child.12
In addition, community-acquired
MRSA has caused at least 1 case of orbital cellulitis in a
non-immunocompromised child and at least 1 case of chronic dacryocystitis
secondary to congenital NLD obstruction.13,14
Thus, healthy infants
can harbor MRSA and pediatric community-acquired MRSA can occur.
and S pneumoniae
still account for between
85% and 98% of all cases of bacterial conjunctivitis.6-8
is also the most common cause of atypical outbreaks of
bacterial conjunctivitis. Therefore, when treating a patient empirically,
fluoroquinolones are a reasonable choice. They are the only class of drugs
effective against both H influenzae
and S pneumoniae
which neither organism has developed significant resistance.15 S
is generally resistant to gentamicin, tobramycin, polymyxin
B/trimethoprim, and azithromycin, and H influenzae
resistance against erythromycin. The fluoroquinolones are also effective
against S aureus
, a less common but still significant cause of bacterial
conjunctivitis. However, methicillin resistance in S aureus
a marker for multidrug resistance, including resistance to the
fluoroquinolones. Of the antibiotics tested by Ocular TRUST, only trimethoprim
retained high efficacy against MRSA in vitro; 95% of MRSA isolates were
susceptible to trimethoprim.15
A potent, highly effective antibiotic eradicates pathogens quickly, reducing the length of time for bacteria to mutate and therefore develop resistance.
— Rudolph S. Wagner, MD
The idea that treating infections with the most potent antibiotic
available can lead to drug resistance is inaccurate. A potent, highly effective
antibiotic eradicates pathogens quickly, reducing the length of time for
bacteria to mutate and therefore develop resistance. Rather, the use of
inadequate doses or tapering of antibiotics in ophthalmic use contributes to
the development of antibiotic resistance. Another factor in clinical practice
is the inappropriate use of systemic antibiotics by physicians and nonadherence
by patients. Other causes of the increase in antibiotic resistance are
widespread use of antibiotics in animal
and the spread of resistant organisms by increased
The US Public Health Service, the CDC, and in-hospital antibiotic
monitoring teams disseminate policies to help reduce the spread of antibiotic
resistance. However, they can only monitor antibiotic use in humans. The use of
antibiotics in agriculture has not been regulated. Food animals receive between
40% and 80% of antimicrobials in the United States each year. Many of these
antibiotics are the same or similar to antibiotics that are used in humans.
Most of these antibiotics, however, are not used to treat disease. Healthy
animals receive low doses of antimicrobial agents in their feed over prolonged
periods of time to promote growth, to increase feed efficiency, and to prevent
disease. Because resistance genes are bred and transferred within environmental
reservoirs that contain bacteria and antibacterial agents in less than
bactericidal concentrations, this nontherapeutic use of antibiotics is likely
to select for organisms with genes conferring resistance to those antibiotics.
Exposure to low dosages of antibiotics over long periods of time creates
selective pressure for organisms to mutate, develop resistance genes, and
transfer these genes horizontally to other organisms.17,18
While bacteria spread genes for antibiotic resistance to other bacteria,
humans disseminate antibiotic resistant strains of bacteria internationally.
Global travel increases the biodiversity of organisms. When bacteria are
introduced to a region where they were previously absent, reduced natural
selection leads to increased genetic drift and increases the number and variety
of strains that develop from that species of bacteria. Certain strains of
were already resistant to methicillin before methicillin
was ever used as an antibiotic. These strains have increased in number and
diversity. New strains can initially be unique to a geographic region until
person-to-person contact spreads these strains across from country to country
and across oceans.19,20
Bacterial Resistance to Fluoroquinolones
Because fluoroquinolones are usually the initial therapy for bacterial
conjunctivitis before the results of cultures are obtained (if conjunctival
swabs for cultures are, in fact, obtained), preventing the development of
fluoroquinolone resistance and increasing fluoroquinolone activity are
important goals. The mechanism of action for all newer fluoroquinolones is
2-fold: they target DNA gyrase and topoisomerase IV. The probability of an
organism developing 2 simultaneous resistant mutations is extremely
Furthermore, topical fluoroquinolones can eradicate bacteria
from the eye quickly in the concentration and dosages in which they are
prescribed, greatly reducing the opportunity for mutations to
Studies have shown that newer fluoroquinolones did not
contribute to resistance of isolates from the conjunctiva, nose, throat, or
However, because of the high level of in vitro MRSA
resistance, the Ocular TRUST study suggests considering alternatives to
fluoroquinolones when MRSA is a likely pathogen (Table 2).15
Click here for larger version of this
In summary, conjunctivitis can have a bacterial, viral, or allergic
etiology. Bacteria are the most common cause of conjunctivitis in children, but
the possibility of conjunctivitis in adolescents and older children should not
be ruled out. Clinicians should be mindful of the likely source of
conjunctivitis when deciding how to treat their patients.
- Rose PW, Harnden A, Brueggemann AB, et al. Chloramphenicol treatment for acute infective conjunctivitis in children in primary care: a randomised double-blind placebo-controlled trial.
- Kowalski RP, Dhaliwal DK. Ocular bacterial infections: current and future treatment options.
Expert Rev Anti Infect Ther. 2005;3(1):131-139.
- Høvding G. Acute bacterial conjunctivitis. Acta Ophthalmol. 2008;86(1):5-17.
- Bodor FF, Marchant CD, Shurin PA, Barenkamp SJ. Bacterial etiology of conjunctivitis-otitis media syndrome.
- Block SL, Hedrick J, Tyler R, et al. Increasing bacterial resistance in pediatric acute conjunctivitis (1997-1998).
Antimicrob Agents Chemother. 2000;44(6):1650-1654.
- Weiss A, Brinser JH, Nazar-Stewart V. Acute conjunctivitis in childhood. J Pediatr. 1993;122(1):10-14.
- Patel PB, Diaz MC, Bennett JE, Attia MW. Clinical features of bacterial conjunctivitis in children.
Acad Emerg Med. 2007;14(1):1-5.
- Meltzer JA, Kunkov S, Crain EF. Identifying children at low risk for bacterial conjunctivitis.
Arch Pediatr Adolesc Med. 2010;164(3):263-267.
- Martin M, Turco JH, Zegans ME, et al. An outbreak of conjunctivitis due to atypical
Streptococcus pneumoniae. N Engl J Med. 2003;348(12):1112-1121.
- Centers for Disease Control and Prevention (CDC). Pneumococcal conjunctivitis at an elementary school — Maine, September 20 - December 6, 2002.
MMWR Morb Mortal Wkly Rep. 2003;52(4):64-66.
- Cavuoto K, Zutshi D, Karp CL, Miller D, Feuer W. Update on bacterial conjunctivitis in South Florida.
- Sahu DN, Thomson S, Salam A, Morton G, Hodgkins P. Neonatal methicillin-resistant
Staphylococcus aureus conjunctivitis. Br J Ophthalmol. 2006;90(6):794-795.
- Vazan DF, Kodsi SR. Community-acquired methicillin-resistant Staphylococcus aureus orbital cellulitis in a non-immunocompromised child.
J AAPOS. 2008;12(2):205-206.
- Kodsi S. Community-acquired methicillin-resistant Staphylococcus aureus in association with chronic dacryocystitis secondary to congenital nasolacrimal duct obstruction.
J AAPOS. 2006;10(6):583-584.
- Asbell P, et al. Presented at: Annual Meeting of the American Society of Cataract and Refractive Surgery; April 3-8, 2009; San Francisco, CA.
- Schlech BA, Blondeau J. Future of ophthalmic anti-infective therapy and the role of moxifloxacin ophthalmic solution 0.5% (VIGAMOX).
Surv Ophthalmol. 2005;50(suppl 1):S64-S67.
- Shea KM. Antibiotic resistance: what is the impact of agricultural uses of antibiotics on children's health?
Pediatrics. 2003;112(1 Pt 2):253-258.
- Shea KM; American Academy of Pediatrics Committee on Environmental Health; American Academy of Pediatrics Committee on Infectious Diseases. Nontherapeutic use of antimicrobial agents in animal agriculture: implications for pediatrics.
- Hershberg R, Lipatov M, Small PM, et al. High functional diversity in Mycobacterium tuberculosis driven by genetic drift and human demography.
PLoS Biol. 2008;6(12):e311.
- Ayliffe GA. The progressive intercontinental spread of methicillin-resistant Staphylococcus aureus.
Clin Infect Dis. 1997;24(suppl 1):S74-S79.
- Comstock TL, Karpecki PM, Morris TW, Zhang JZ. Besifloxacin: a novel anti-infective for the treatment of bacterial conjunctivitis.
Clin Ophthalmol. 2010;4:215-225.
- Nafziger AN, Bertino JS Jr. Besifloxacin ophthalmic suspension for bacterial conjunctivitis.
Drugs Today (Barc). 2009;45(8):577-588.
- Lichtenstein SJ, et al. Paper presented at: American Association for Pediatric Ophthalmology and Strabismus (AAPOS) 36th Annual Meeting; April 14-18, 2010; Orlando, FL.