Neonatal Conjunctivitis (Ophthalmia Neonatorum)

Key Points at a Glance

Highlights of This Disease

• Neonatal conjunctivitis (ophthalmia neonatorum) is inflammation of the conjunctiva occurring within the first 28 days of life.
• The global incidence is 2.04%, higher in low-income countries, and risk increases with vaginal delivery and preterm birth. ¹⁾
• The cause can be estimated based on the time of onset, and is classified into chemical, gonococcal, chlamydial, and viral types.
• Gonococcus is the only bacterium that can directly invade healthy corneal epithelium, posing a risk of corneal perforation and blindness.
• Chlamydial infection is accompanied by upper respiratory tract inflammation and pneumonia in 10–20% of cases, requiring systemic management.
• Early diagnosis and treatment lead to a good prognosis, while delayed treatment can result in serious complications such as orbital cellulitis. ³⁾
• Prophylaxis immediately after birth with WHO-recommended eye drops is effective and reduces the incidence of all-cause conjunctivitis. ²⁾

1. What is neonatal conjunctivitis?

Neonatal conjunctivitis (ophthalmia neonatorum) is inflammation of the conjunctiva occurring within 28 to 30 days after birth. Historically, in 1880, Crede introduced 1% silver nitrate eye drops, which greatly contributed to the prevention of gonococcal conjunctivitis. Currently, prophylaxis with antibacterial eye drops is the standard.

The global incidence is 2.04% (95% CI 0.70–5.79%), and the prevalence is 7.79% (95% CI 2.93–19.10%). ¹⁾ There is significant regional variation, with rates of 6.90% in low-income countries and 1.36% in high-income countries. ¹⁾ It is estimated that approximately 10,000 cases occur worldwide each year. ¹⁾

The mode of delivery and gestational age also affect the incidence rate.

• Vaginal delivery: incidence rate 4.74%
• Cesarean section: incidence rate 1.88%
• Preterm infants: incidence rate 3.08%
• Full-term infants: incidence 1.16%¹⁾

Etiology is broadly classified into chemical, bacterial, and viral causes. Among bacterial causes, chlamydia is the most frequent, while gonococcus leads to the most severe outcomes.

Q How often does neonatal conjunctivitis occur?

A

The global incidence is approximately 2.04%, with an estimated 10,000 cases per year. ¹⁾ There are regional differences: 1.36% in developed countries, while it reaches 6.90% in low-income countries.

2. Main Symptoms and Clinical Findings

Slit-lamp photograph of neonatal conjunctivitis

Linton E, Hardman L, Welburn L, et al. Adult conjunctivitis secondary to dual infection with Chlamydia trachomatis and Neisseria gonorrhoeae - A case report. Am J Ophthalmol Case Rep. 2018 Nov 14;13:6. Figure 1. PMCID: PMC6247407. License: CC BY.

This slit-lamp photograph shows mucopurulent discharge and corneal thinning near the limbus. It helps to concretely understand the situation where severe conjunctival infection is accompanied by corneal damage.

Subjective Symptoms

Newborns cannot express symptoms. Parents or medical staff must observe objectively.

• Eye discharge: varies from serous to purulent depending on the cause
• Eyelid swelling: in severe cases, the eyeball may be difficult to see
• Conjunctival injection: severity varies depending on the cause
• Lacrimation: observed along with increased discharge
• Conjunctival edema: becomes prominent in severe cases

In newborns, there is decreased tear secretion, lack of secretory IgA, and reduced lysozyme activity, making them vulnerable to infection.

Clinical Findings

The timing of onset is the most important clue for determining the cause. Characteristic findings for each cause are shown below.

Chemical

Onset: Within 24 hours after birth

Findings: Only mild redness and tearing

Course: Resolves spontaneously in 2–4 days

Gonococcal

Onset: 1–3 days after birth

Findings: Profuse purulent discharge (gonococcal ophthalmia neonatorum), severe eyelid swelling

Characteristic: The only bacterium capable of adhering to and invading healthy corneal epithelium. Risk of corneal ulcer → perforation → endophthalmitis.

Chlamydial

Onset: 3–10 days after birth

Findings: Pseudomembranous conjunctivitis (no follicle formation), velvety hyperemia of the palpebral conjunctiva, bloody discharge

Complications: Nasopharyngitis and pneumonia occur in 10–20% of cases

Viral (HSV)

Onset: 1–2 weeks after birth

Findings: Fine dendritic or geographic corneal ulcers (newborns may lack characteristic findings)

Caution: Neonatal herpes simplex virus infection can progress to systemic infection

Moraxella species develop after 7–10 days of life and are called pseudogonococcal conjunctivitis.

Q Can the cause be estimated based on the time of onset?

A

The time of onset is the most important clue for estimating the cause. Chemical conjunctivitis typically occurs within 24 hours, gonococcal at 1–3 days, chlamydial at 3–10 days, and herpes simplex virus at 1–2 weeks after birth. However, microbiological testing is necessary for a definitive diagnosis.

3. Causes and Risk Factors

The most common route of infection is through the birth canal. Maternal sexually transmitted infections are the main risk factors.

• Gonorrhea: The mother-to-child transmission rate is 30–50%²⁾
• Chlamydia: The incidence rate from untreated mothers is 30–40%
• E. coli: maternal colonization rate 19.9%, vertical transmission rate 21.4%⁸⁾

Other risk factors include the following:

• Maternal sexually transmitted infections (gonorrhea, chlamydia infection)
• Premature rupture of membranes
• Premature birth
• Vaginal delivery
• Inadequate prophylactic eye drops immediately after birth

Prevention

Prophylactic eye drops, starting with the Credé method (1% silver nitrate), are effective. A Cochrane review of 30 trials involving 79,198 newborns showed that the use of prophylactic agents reduces the incidence of all-cause conjunctivitis (moderate certainty). ²⁾

The five prophylactic agents recommended by the WHO are as follows: ²⁾

• Tetracycline 1%
• Erythromycin 0.5%
• Povidone-iodine 2.5%
• Silver nitrate 1%
• Chloramphenicol 1%

Prevention and daily care

Screening and treatment for sexually transmitted infections during pregnancy are the basis for preventing neonatal conjunctivitis. If gonococcal or chlamydial infection is detected, receive appropriate treatment before delivery. Prophylactic eye drops immediately after birth are administered by the medical facility. If eye discharge or eyelid swelling is observed after delivery, consult an ophthalmologist immediately.

Q Can neonatal conjunctivitis be prevented by cesarean section?

A

Even with cesarean section, the incidence is reported to be 1.88%, so it cannot be completely prevented. ¹⁾ Because routes other than birth canal infection (such as ascending infection) may be responsible, caution is necessary even after cesarean section.

4. Diagnosis and Examination Methods

Differentiation based on the time of onset is most important; refer to the “Clinical Findings” section to estimate the cause. Microbiological testing is essential for a definitive diagnosis.

Smear microscopy and staining

The combination of onset timing and staining findings is key to diagnosis.

Staining method	Target	Findings observed
Gram stain	Gonococcus	Gram-negative diplococci phagocytized by neutrophils
Giemsa stain	Chlamydia	Inclusion bodies (Prowazek bodies)
Fluorescein staining	Corneal lesions	Check for epithelial defects under cobalt blue light

Culture and genetic testing

• Culture (gonococcus): Incubate on chocolate agar medium in 5–10% CO2 environment
• PCR method: Excellent sensitivity and specificity; useful for both chlamydia and gonococcus
• Real-time PCR, SDA, TMA: Used as nucleic acid amplification methods
• Immunochromatography: Enables rapid diagnosis

Differential Diagnosis

It is important to exclude diseases with similar symptoms.

• Dacryocystitis: Regurgitation of discharge upon compression of the nasal root
• Congenital glaucoma: Corneal enlargement and opacity, elevated intraocular pressure
• Nasolacrimal duct obstruction: Mainly tearing, few signs of infection
• Orbital cellulitis: Severe case with eyelid redness, induration, and proptosis

5. Standard treatment

Treatment is selected according to the cause. We focus on treatments in Japan and also supplement with standard protocols overseas.

Standard treatment in Japan

The following is the treatment protocol in Japan.

• Bacterial (general): Bestron ophthalmic solution 0.5%, 5 times daily
• Gonococcal: Bestron 0.5% 8 times daily + Rocephin intravenous drip 1 g once daily
• Chlamydial: Tarivid ophthalmic ointment 0.3% 5 times daily for 8 weeks; for severe cases, Zithromax 10 mg/kg for 3 days
• Herpetic: Zovirax ophthalmic ointment 5 times daily

Standard Treatment Outside Japan

Cause	Recommended Treatment
Chemical	Artificial tears QID (wait for spontaneous resolution)
Gonococcal	Ceftriaxone 25–50 mg/kg single dose
Chlamydial	Azithromycin 20 mg/kg for 3 days4)
Herpes simplex virus	Acyclovir IV 45 mg/kg/day for 14–21 days

Oral erythromycin is effective as systemic treatment for chlamydial conjunctivitis, but caution is needed regarding its association with infantile hypertrophic pyloric stenosis (IHPS).

Precautions for ceftriaxone administration in neonates

When using ceftriaxone in neonates, there is a risk of hyperbilirubinemia. ³⁾ For severe cases such as orbital cellulitis, cefotaxime 50 mg/kg QID for 14 days is recommended. ³⁾ Delayed treatment can lead to serious complications such as orbital cellulitis, so prompt initiation of therapy is important.

Q What are the precautions when using ceftriaxone in neonates?

A

In neonates, the use of ceftriaxone carries a risk of hyperbilirubinemia. ³⁾ Therefore, in severe cases complicated by orbital cellulitis, the use of cefotaxime is recommended. When administering, it is important to select the drug after confirming the neonate’s jaundice status.

6. Pathophysiology and Detailed Pathogenesis

Immunological Vulnerability of Neonates

The neonatal eye is more vulnerable to infection compared to adults. The main factors are as follows:

• Decreased tear secretion
• Lack of secretory IgA
• Decreased lysozyme activity
• Underdevelopment of subconjunctival lymphoid tissue (contributing to pseudomembrane formation)

Pseudomembrane is fibrin, neutrophils, and inflammatory exudate attached to the conjunctiva. In chlamydial conjunctivitis, follicles do not form due to underdeveloped adenoid tissue (pseudomembranous conjunctivitis).

Mechanism of gonococcal infection

Gonococcus is the only bacterium that can infect even eyes with healthy corneal epithelium. Its pathogenicity is due to the following mechanisms.

• Pili: Mediate adhesion to epithelial cells
• Outer membrane proteins (OMPs): involved in cell invasion
• LOS (lipooligosaccharide, endotoxin): triggers a strong inflammatory response

In Kenya, corneal lesions have been reported in up to 16% of affected children, ²⁾ and early treatment is essential.

Mechanism of Chlamydia infection

Chlamydia (Chlamydia trachomatis) is an obligate intracellular parasite. Outside cells, it exists as the infectious elementary body (EB), and inside cells it transforms into the replicative reticulate body (RB). It forms inclusion bodies (Prowazek bodies) within infected epithelial cells. Adult inclusion conjunctivitis is characterized by many large, solid follicles in the lower conjunctival fornix, whereas neonatal inclusion conjunctivitis typically develops around 7 days after birth and lacks follicles due to underdeveloped lymphoid tissue.

7. Latest Research and Future Prospects (Research Stage Reports)

For Patients: Please Read Carefully

The following content is currently at the research stage or under clinical trials and is not standard treatment available at general hospitals. It is reference information for professionals regarding future medical developments.

Neonatal conjunctivitis caused by emerging and rare pathogens

In addition to the traditional major pathogens, reports of new pathogens are accumulating.

Mechel et al. (2021) reported the first case of neonatal conjunctivitis due to SARS-CoV-2 in a 4-day-old girl. ⁷⁾ She presented with subconjunctival hemorrhage and mucopurulent discharge, which resolved spontaneously within 8 days.

Albuquerque et al. (2024) reported that Neisseria meningitidis accounts for 1–2% of neonatal conjunctivitis cases, with a 10–29% risk of progression to invasive disease. ⁵⁾ Complete recovery was achieved with intravenous cefotaxime 200 mg/kg/day for 7 days.

Merzouk et al. (2025) reported that enteric gram-negative rods (e.g., E. coli) are increasing in NICU-associated infections. The maternal E. coli colonization rate was 19.9%, and the vertical transmission rate was 21.4%. ⁸⁾

Das (2023) reported that in a Korean study, Acinetobacter baumannii accounted for 1.2% of neonatal conjunctivitis cases, while S. aureus accounted for 52.4%. ⁶⁾ Multidrug-resistant A. baumannii has become a problem as a cause of NICU-associated nosocomial infections.

Optimization of Prophylactic Agents

A Cochrane review (Malik and Gilbert 2022) concluded that no superiority among prophylactic agents has been established to date, and the selection of the optimal prophylactic agent remains a topic for future research. ²⁾

Treatment Delay and Complications

Law et al. (2024) reported two cases of neonatal conjunctivitis that progressed to orbital cellulitis due to treatment delay. ³⁾ This again highlights the importance of early diagnosis and treatment intervention.

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8. References

1. Asiamah R, Owusu G, Amoako PT, et al. Epidemiology of ophthalmia neonatorum: a systematic review and meta-analysis. BMC Pediatr. 2025;25:31.

2. Malik ANJ, Gilbert C. Cochrane corner: interventions for preventing ophthalmia neonatorum. Eye. 2022;36:356-357.

3. Law NL, Tan VC, Lim TH, et al. Ophthalmia neonatorum complicated with neonatal orbital cellulitis: A case series. Malays Fam Physician. 2024;19:5.

4. Nwokeji I, Ding K, Ketner S. A Case of Neonatal Chlamydial Conjunctivitis. Cureus. 2024;16(7):e64463.

5. Albuquerque C, Dias ME, Pelicano M, et al. Neisseria meningitidis: The Unforeseen Agent of Acute Neonatal Conjunctivitis. Cureus. 2024;16(7):e65681.

6. Das G. Acinetobacter baumannii ophthalmia neonatorum - A very rare presentation. Indian J Ophthalmol. 2023;71:2595-2597.

7. Mechel E, Trinh M, Kodsi S, et al. Ophthalmia neonatorum as the presenting sign of SARS-CoV-2. J AAPOS. 2021;25:230-231.

8. Merzouk B, Schwartzman K, Yossuck P, et al. A Rare Case of Neonatal Escherichia coli Conjunctivitis With Maternal Asymptomatic Bacteriuria. Cureus. 2025;17(9):e92936.