Bacterial conjunctivitis and keratitis in children: diagnosis and treatment

Bacterial conjunctivitis in children is an acute inflammation of the conjunctiva, most often caused by typical childhood pathogens such as Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. The disease presents with redness, a gritty sensation, lacrimation, and a characteristic purulent discharge that causes the eyelids to stick together, especially in the morning. In some children, the bacterial inflammation can spread to the cornea, resulting in keratitis, which is more dangerous due to the risk of clouding and decreased vision. [1]

Most episodes of bacterial conjunctivitis are self-limited within 7-10 days, but topical antibacterial agents moderately accelerate clinical recovery and bacterial clearance, which is important for the child's comfort and reducing absences from daycare or school. Antibiotics are indicated for clear signs of bacterial infection, severe discomfort, in organized groups, and in children wearing contact lenses. [2]

Keratitis—inflammation of the cornea—is considered an emergency. In children, contact lens wear is a leading risk factor, especially if hygiene and wearing schedule are poor. Keratitis causes pain, photophobia, visual impairment, and severe lacrimation; it requires urgent evaluation and initiation of antimicrobial therapy, sometimes with cultures and enhanced treatment regimens. [3]

A separate clinical situation is ophthalmia neonatorum, when conjunctival inflammation is caused by Neisseria gonorrhoeae or Chlamydia trachomatis during the first 28 days of life. These cases require systemic therapy and examination of the mother and contacts, as topical drops are ineffective. Early diagnosis and appropriate systemic treatment prevent severe complications. [4]

Code according to ICD 10 and ICD 11

In the International Classification of Diseases, Tenth Revision, bacterial conjunctivitis is coded under block H10 "Conjunctivitis." In practice, the type and location are specified: "mucopurulent conjunctivitis" is coded under H10.0 with specific details for the eyes, and acute unspecified forms are coded under H10.3. Keratitis is classified under block H16 "Keratitis," which includes corneal ulcer, superficial keratitis without conjunctivitis, keratoconjunctivitis, and other subheadings that allow for the severity and characteristics of the disease to be recorded. [5]

The International Classification of Diseases, Eleventh Revision, uses section 9A60 "Conjunctivitis" with subcategory 9A60.3 "Mucopurulent conjunctivitis," as well as 9A60.1 "Follicular conjunctivitis," and other entries for precise classification. This approach is convenient for epidemiological surveillance and insurance reporting. For corneal lesions, the categories of the section "Corneal diseases" are used, and, if necessary, post-coordination by severity and complications is added. [6]

Table 1. Correspondence of main codes

Clinical situation	International Classification of Diseases-10	International Classification of Diseases-11
Mucopurulent conjunctivitis	H10.0 (+ clarification on the eyes)	9A60.3
Acute conjunctivitis, unspecified	H10.3	9A60.Z
Keratitis, corneal ulcer	H16.0	see the section "Corneal diseases"
Keratoconjunctivitis	H16.2	see the section "Corneal diseases"

Epidemiology

Bacterial conjunctivitis is one of the most common causes of "red eye" in children, especially in institutional settings. The most common pathogens in childhood are Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. The disease is easily transmitted by contact with others when overall hygiene is suboptimal. [7]

Most episodes are benign and resolve within 1-2 weeks. However, topical antibiotics moderately shorten the duration of symptoms and accelerate bacterial clearance, reducing missed visits to childcare facilities and the burden on the family. The greatest effect is observed in the first 2-5 days of treatment. [8]

Bacterial keratitis in children is less common than conjunctivitis, but poses a greater threat to vision. Contact lens wear is recognized as a leading risk factor, including in orthokeratology regimens. Failure to disinfect contact lens cases, overnight wear, and swimming with lenses significantly increase the risk of Pseudomonas infection. [9]

Ophthalmia neonatorum occurs in 2-12% of infants and requires organized screening and clear care pathways. In developed countries, prophylactic measures at birth and antenatal care of mothers have reduced the incidence of severe gonococcal cases, but chlamydial infections remain a common problem. [10]

Reasons

Bacterial conjunctivitis is caused by the invasion of microorganisms into the conjunctival epithelium, causing local inflammation and exudation. Haemophilus influenzae and Streptococcus pneumoniae are common in children, while Moraxella catarrhalis and Staphylococcus aureus are less common. Clinically, this is accompanied by a watery-purulent discharge and morning eyelid adhesion. [11]

Keratitis in children most often occurs when the cornea's protective barrier is damaged. Contact lens wear, microtrauma, and dry surface create an entry point for bacteria. Pseudomonas aeruginosa is associated with contact lenses and can quickly cause a central infiltrate with stromal melting, which threatens perforation. [12]

Perinatal infections play a significant role in newborns. Neisseria gonorrhoeae causes a hyperacute purulent process with copious discharge and edema, while Chlamydia trachomatis has a subacute course and is often associated with pneumonitis. These pathogens require systemic therapy for the child and treatment of the mother and sexual partners. [13]

Risk factors

Household risk factors include close-knit groups of children, poor hand hygiene, eye rubbing, and sharing towels. These circumstances increase the likelihood of bacterial transmission and recurrence within the family. Improving hygiene and educating the child reduces the frequency of episodes. [14]

Medical risk factors include recent colds, blepharitis, tear drainage obstruction, and the use of topical corticosteroids for other reasons. These conditions impair local immunity and tear film stability. Correction of associated conditions reduces the risk of recurrence. [15]

The main risks for keratitis are contact lenses, microtrauma, and swimming with lenses in. Overnight wear, poor disinfection of the lens case, and use of tap water for care increase the risk of Pseudomonas infection and severe progression. Avoiding contact lenses during the illness and replacing the lens case are essential. [16]

Table 2. Risk factors and mitigation measures

Factor	Why is it important?	What to recommend to a family
Children's group	Contact transmission	Hand washing, separate towels
Rubbing eyes	Microdamage	Training, rewetting drops
Contact lenses	Pseudomonas risk	Taking a break from wearing, replacing the container
Topical steroids	Weakening of local defenses	Strict indications, physician supervision

Pathogenesis

In bacterial conjunctivitis, microorganisms adhere to the epithelium, triggering the release of proinflammatory mediators and an influx of neutrophils. This explains the watery-purulent nature of the discharge and the pronounced morning drooping of the eyelids. In children, the inflammation spreads rapidly due to the rich vascular network and active mucosal reactivity. [17]

In keratitis, disruption of the corneal epithelial barrier is key. Bacteria and their toxins initiate necrosis and stromal melting. Pseudomonas aeruginosa is characterized by rapid progression with a central gray, soupy infiltrate, requiring immediate intensive therapy and frequent cultures for targeted treatment. [18]

While the immune response limits infection, it can also exacerbate tissue damage. Therefore, in severe keratitis, after confirming a response to antibiotics within 24-48 hours, short courses of topical steroids are considered in selected cases under strict supervision, avoiding them if a fungal, nocardiotic, or acanthamoebic cause is suspected. [19]

Table 3. Pathogenetic links and therapeutic goals

Link	Manifestation	Goal of treatment
Bacterial adhesion and growth	Purulent discharge	Local antibiotic, hygiene
Damage to the epithelium	Pain, photophobia	Surface protection, antibacterial therapy
Immune stromal inflammation	Clouding, risk of scarring	Inflammation control, in select cases - steroids under cover

Symptoms

Bacterial conjunctivitis is characterized by purulent discharge, eyelid adhesion, redness, and discomfort. Itching is less pronounced than with allergic conjunctivitis. Visual impairment is usually moderate and is associated with discharge and lacrimation, not corneal damage. [20]

Keratitis causes severe pain, photophobia, lacrimation, and a foreign body sensation; vision is noticeably impaired. These symptoms are aggravated by blinking and in bright light. A history of contact lens use increases the likelihood of a Pseudomonas infection. [21]

In newborns, the gonococcal form begins rapidly, with massive purulent discharge and eyelid edema, while the chlamydial form is subacute, often bilateral. In either case, systemic therapy and an assessment for concomitant infections in both the child and mother are required. [22]

Table 4. Differences in the main causes of "red eye" in children

Sign	Bacterial conjunctivitis	Viral	Allergic	Herpetic
Separable	Purulent	Watery	Mucous "threads"	Mucous, with corneal ulcer pain
Morning gluing	Often	Less often	Rarely	Possible
Pain, photophobia	Moderate	Moderate	The itch is leading	Often expressed
Corneal epithelial defect	No	Sometimes infiltrates	No	Tree-like defects

Classification, forms and stages

Bacterial conjunctivitis is classified as acute, subacute, and chronic based on the duration of symptoms, and as mucopurulent and hyperacute based on the severity of discharge. The hyperacute form suggests Neisseria gonorrhoeae and requires immediate systemic treatment. [23]

Keratitis is classified by infiltrate location, lesion depth, and severity. Central location, diameter greater than 2 mm, deep stroma, atypical appearance, and poor response to initial therapy are signs of severe progression and indications for culture and expanded regimens. Children with contact lenses have a high risk of gram-negative flora. [24]

The natural course with adequate therapy includes a gradual reduction in pain, photophobia, and infiltrate size over 48-72 hours. A lack of progression is a reason to reconsider the diagnosis, treatment plan, and microbiology results. [25]

Complications and consequences

Untreated conjunctivitis can spread to the cornea, leading to keratitis and temporary vision loss. Long, unmonitored courses increase the risk of side effects and the development of resistance. Proper duration and choice of medication minimize these risks. [26]

Keratitis is dangerous due to corneal opacity, astigmatism, and persistent loss of best-corrected visual acuity. Pseudomonas-related keratitis can lead to rapid stromal fusion and perforation, requiring emergency measures and sometimes surgery. [27]

In neonates with hyperacute gonococcal infection, the risk of perforation is particularly high, and in chlamydial infection, the risk of pneumonitis is high. Timely systemic therapy significantly reduces the incidence of severe outcomes. [28]

Table 5. Main risks and prevention of complications

Risk	Mechanism	How to reduce
Transition to the cornea	Spread of infection	Early therapy, control
Corneal opacity	Stromal inflammation	Adequate regimen, pain and inflammation control
Perforation	Melting of the stroma	Urgent intensive care, surgery if necessary

When to see a doctor

An immediate ophthalmological examination is necessary if you experience severe pain, severe photophobia, a sudden decrease in vision, the appearance of a white or gray spot on the cornea, or if you wear contact lenses while experiencing a red eye. These are signs of possible keratitis. [29]

Infants with any purulent conjunctivitis require urgent in-person evaluation, as ophthalmia neonatorum requires systemic treatment and respiratory monitoring. Delay in therapy increases the risk of severe outcomes. [30]

If there is no improvement within 48-72 hours of starting treatment, the diagnosis and treatment plan should be reviewed, and the need for culture and expansion of coverage should be discussed. This is especially true for children with contact lenses and large central infiltrates. [31]

Table 6. Red flags requiring urgent attention

Sign	Possible cause	Act One
Severe pain, "fog" in front of the eye	Keratitis	See an ophthalmologist urgently
White spot on the cornea	Infiltrate, ulcer	Start intensive treatment, culture as indicated
A baby with purulent discharge	Ophthalmia neonatorum	Hospitalization, systemic therapy

Diagnostics

At the initial stage, the diagnosis of bacterial conjunctivitis is established clinically by the combination of purulent discharge, morning "stickiness," and redness, while visual acuity is usually preserved. Routine testing is not required unless there is an atypical course or severe symptoms. [32]

If keratitis is suspected, a slit lamp examination, fluorescein staining, assessment of the size and location of the infiltrate, and measurement of intraocular pressure are performed. This helps determine the severity, risk of complications, and the need for culture. [33]

Cultures and smears are indicated for central infiltrates greater than 2 mm in diameter, deep or chronic lesions, failure to respond to initial therapy, or suspected atypical flora. Prior to sampling, antibiotic instillation should be avoided whenever possible to avoid reducing diagnostic value. [34]

Table 7. Indications for microbiological examination in keratitis

Situation	Why take seeding?
Central, large, deep infiltrate	High risk of scarring and vision loss
Atypical course, injury from plant material	Exclude fungus and rare flora
No improvement within 48-72 hours	Check resistance and change the scheme

Differential diagnosis

Bacterial conjunctivitis must be distinguished from viral, allergic, and herpetic infections. Bacterial conjunctivitis is characterized by purulent discharge and pronounced morning congestion, viral conjunctivitis by watery discharge and follicular lesions, and allergic conjunctivitis by predominant itching and thread-like discharge. Herpetic keratoconjunctivitis is accompanied by pain, decreased corneal sensitivity, and dendritic epithelial defects. [35]

In children wearing contact lenses, pain and photophobia are always considered for keratitis, especially Pseudomonas keratitis, which is aggressive. A slit lamp examination, corneal staining, and a history of lens wear and hygiene can help differentiate the two. [36]

Table 8. Key differences in clinical presentation

Sign	Bacterial conjunctivitis	Viral	Allergic	Bacterial keratitis
Nature of discharge	Purulent	Watery	Mucous	Often scanty, pain is pronounced
Changes in vision	Minimum	Minimum	Minimum	Significant
Pain and photophobia	Moderate	Moderate	The itch is leading	Strong

Treatment

In most children, bacterial conjunctivitis is treated with topical antibiotics for 5-7 days. Either erythromycin ointment is applied in a 1 cm strip 4 times daily, which is convenient for infants, or trimethoprim plus polymyxin B drops, 1-2 drops 4 times daily. These regimens are effective against the main childhood pathogens and are well tolerated. Follow-up is recommended if there is no improvement after 48-72 hours. [37]

An alternative is 1% azithromycin drops, administered twice daily for 2 days, then once daily for 5 days, which results in only 9 drops per course and improves compliance. For children who wear contact lenses or if Pseudomonas infection is suspected, fluoroquinolones in drops with a coating against gram-negative bacteria are preferred. Lens wear is discontinued until complete recovery, and the container is changed. [38]

For bacterial keratitis, treatment begins immediately. For mild to moderate cases, monotherapy with a modern fluoroquinolone is possible, with a frequency of up to hourly during the first 24 hours and then gradually tapering. For severe, central, deep, or rapidly progressing ulcers, fortified broad-spectrum agents are used as recommended by an ophthalmologist, with cultures and progress monitoring. [39]

The role of steroids in keratitis is limited. The addition of a topical steroid anti-inflammatory agent is considered only after 24-48 hours of a clear response to the antibiotic and a known pathogen, avoiding this approach if fungi, nocardia, or acanthamoeba are suspected. A large randomized trial found no overall improvement in vision after 3 months with the addition of steroids, but certain subgroups of severe ulcers may have benefited from early addition. The decision should be made by a specialist. [40]

Analgesia and surface protection are standard: cycloplegics as indicated for pain relief, preservative-free artificial tears, avoidance of contact lenses, and a gentle regimen. If there is a risk of melting, systemic stromal support measures are sometimes added at the specialist's discretion. Patients are monitored dynamically with photographic documentation. [41]

Table 9. Empirical regimens for childhood bacterial conjunctivitis

Scenario	Preparation	Typical mode
Most cases	Erythromycin ointment	1 cm strip 4 times a day for 7 days
Most cases	Trimethoprim plus polymyxin B	1-2 drops 4 times a day for 7 days
Convenient regimen with low commitment	Azithromycin 1% drops	2 times a day for 2 days, then 1 time a day for 5 days
Wearing contact lenses	Fluoroquinolone drops	According to the doctor's instructions, usually more often at the beginning

Table 10. Principles of treatment of bacterial keratitis

Situation	Tactics	Comment
Mild to moderate ulcers	Modern fluoroquinolone, frequent instillations	With a gradual decrease in frequency
Severe, central, deep ulcers	Fortified preparations, crops	Urgently, according to the ophthalmologist's protocols
Steroids	Consider later, in the background of the answer	Avoid if fungus, nocardia, or acanthamoeba are suspected.

Ophthalmia neonatorum: What's important to know?

If Neisseria gonorrhoeae is suspected, the child receives a single dose of ceftriaxone intramuscularly or intravenously at 25-50 mg per kg of body weight, with caution in newborns with hyperbilirubinemia and with the choice of an alternative based on the indications. Local therapy complements, but does not replace, systemic therapy. Culture and examination of the mother and partners are mandatory. [42]

For Chlamydia trachomatis, systemic therapy is prescribed with erythromycin 50 mg/kg body weight per day in 4 doses for 14 days or azithromycin 20 mg/kg once a day for 3 days. It is important to monitor the child due to the risk of chlamydial pneumonitis and to warn the family about the need for treatment of the mother and partners. [43]

Table 11. Systemic therapy for ophthalmia neonatorum

Presumed causative agent	Preparation	Orientation mode
Neisseria gonorrhoeae	Ceftriaxone	25-50 mg/kg once intramuscularly or intravenously
Chlamydia trachomatis	Erythromycin	50 mg/kg per day, 4 doses, 14 days
Chlamydia trachomatis	Azithromycin	20 mg/kg once a day, 3 days

Prevention

Family prevention measures include frequent hand washing, individual towels and pillowcases, avoiding eye rubbing, and avoiding sharing cosmetics and contact lens solutions. During the illness, the child should not wear contact lenses, and the lens case and solution should be replaced. [44]

In children's groups, prevention relies on hygiene training for staff and children, prompt isolation of sick individuals who feel unwell, and disinfection of surfaces. These measures are especially important during outbreaks of conjunctivitis. [45]

In healthcare settings, strict control of instrument reprocessing and the use of disposable consumables during ocular surface procedures is required to prevent cross-transmission. [46]

Forecast

With bacterial conjunctivitis, the prognosis is favorable; symptoms usually subside within 1-2 weeks. Antibiotics shorten the duration of symptoms and accelerate bacterial clearance, especially in the first few days. Follow-up is recommended if there is no improvement within 48-72 hours. [47]

In bacterial keratitis, the outcome depends on the prompt initiation of therapy and the location and depth of the infiltrate. Early, intensive treatment, with culture and correction if necessary, allows for the preservation of high vision in most children. Delayed treatment increases the risk of scarring. [48]

In newborns, the prognosis is determined by the speed of pathogen recognition and the initiation of systemic therapy. Organized routes and contact monitoring reduce the risk of severe consequences. [49]

Frequently asked questions

Do all children with red eyes need antibiotics?
No. Antibiotics are not indicated for viral or allergic cases. If there are signs of a bacterial infection in children, antibiotics moderately speed recovery and are recommended, especially in cases of severe discomfort and in groups. [50]

When can I return to kindergarten or school?
Once my health improves and hygiene is maintained, most guidelines allow for attendance without the need for a medical certificate if the condition is mild. For keratitis and in infants, the decision is made individually by a doctor. [51]

Are smears and cultures necessary?
Most children with typical conjunctivitis do not. Cultures are needed in cases of severe keratitis, central and deep infiltrates, atypia, or lack of improvement within 48-72 hours. [52]

Are steroids dangerous for keratitis?
They are used only as an adjunct and only after antibiotics have responded, usually within 24-48 hours, and for a known pathogen. If fungi, nocardia, or acanthamoeba are suspected, steroids are contraindicated. A large study showed no overall benefit to vision. [53]