Acute Bacterial Conjunctivitis

ByZeba A. Syed, MD, Wills Eye Hospital
Reviewed/Revised Apr 2023
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Acute conjunctivitis can be caused by numerous bacteria. Symptoms are hyperemia, lacrimation, irritation, and discharge. Diagnosis is clinical. Treatment is with topical antibiotics, augmented by systemic antibiotics in more serious cases.

Most bacterial conjunctivitis is acute; chronic bacterial conjunctivitis may be caused by Chlamydia and rarely Moraxella. Chlamydial conjunctivitis includes trachoma and adult inclusion conjunctivitis or neonatal inclusion conjunctivitis.

(See also Overview of Conjunctivitis.)

Etiology of Acute Bacterial Conjunctivitis

Bacterial conjunctivitis is usually caused by Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus species, Moraxella catarrhalis or, less commonly, Chlamydia trachomatis. Neisseria gonorrhoeae causes gonococcal conjunctivitis, which usually results from sexual contact with a person who has a genital infection.

Ophthalmia neonatorum (neonatal conjunctivitis) results from a maternal gonococcal and/or chlamydial infection. Neonatal conjunctivitis occurs in 20 to 40% of neonates delivered through an infected birth canal.

Symptoms and Signs of Acute Bacterial Conjunctivitis

Symptoms are typically unilateral but frequently spread to the opposite eye within a few days. Discharge is typically purulent.

The bulbar and tarsal conjunctivae are intensely hyperemic and edematous. Petechial subconjunctival hemorrhages, chemosis, photophobia, and an enlarged preauricular lymph node are typically absent. Eyelid edema is often moderate.

With adult gonococcal conjunctivitis, symptoms develop 12 to 48 hours after exposure. Severe eyelid edema, chemosis, and a profuse purulent exudate are typical. Rare complications include corneal ulceration, abscess, perforation, panophthalmitis, and blindness.

Ophthalmia neonatorum caused by gonococcal infection appears 2 to 5 days after delivery. With ophthalmia neonatorum caused by a chlamydial infection, symptoms appear within 5 to 14 days. Symptoms of both are bilateral, intense papillary conjunctivitis with eyelid edema, chemosis, and mucopurulent discharge.

Diagnosis of Acute Bacterial Conjunctivitis

  • Clinical evaluation

  • Sometimes culture of conjunctival smear or scrapings

Diagnosis of conjunctivitis and differentiation between bacterial, viral, and noninfectious conjunctivitis (see table Differentiating Features in Acute Conjunctivitis) are usually clinical. However, differentiation between bacterial and viral conjunctivitis is often difficult based on clinical criteria because symptoms often overlap. Smears and bacterial cultures should be done in patients with severe symptoms, immunocompromise, ineffective initial therapy, or a vulnerable eye (eg, after a corneal transplant, in exophthalmos due to Graves disease). Smears and conjunctival scrapings should be examined microscopically and stained with Gram stain to identify bacteria and stained with Giemsa stain to identify the characteristic epithelial cell basophilic cytoplasmic inclusion bodies of chlamydial conjunctivitis (see ).

Table
Table

Treatment of Acute Bacterial Conjunctivitis

  • Antibiotics (topical for all causes except gonococcal and chlamydial)

Bacterial conjunctivitis is very contagious, and standard infection control measures should be followed.

Clinicians avoid transmitting infection if they do the following:

  • Use hand sanitizer or wash their hands properly (fully lather hands, scrub hands for at least 20 seconds, rinse well, and turn off the water using a paper towel)

  • Disinfect equipment after examining patients

Patients should do the following:

  • Use hand sanitizer and/or wash their hands thoroughly after touching their eyes or nasal secretions

  • Avoid touching the noninfected eye after touching the infected eye

  • Avoid sharing towels or pillows

  • Avoid swimming in pools

If neither gonococcal nor chlamydial

trachomasexually transmitted infections and the local public health authorities (at least in the United States) need to be notified.

Key Points

  • Acute bacterial conjunctivitis tends to differ from viral conjunctivitis by the presence of purulent discharge and the absence of chemosis and preauricular adenopathy.

  • Forms of bacterial conjunctivitis that need to be treated differently include neonatal conjunctivitis, gonococcal conjunctivitis, trachoma, and inclusion conjunctivitis (a type of chlamydial conjunctivitis).

  • Diagnosis is usually clinical.

  • Treatment includes measures to prevent spread and antibiotics (topical, such as a fluoroquinolone, for causes except gonococcal and chlamydial).

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