Definition of Neonatal conjunctivitis:

Neonatal conjunctivitis is swelling (inflammation) or infection of the tissue lining the eyelids in a newborn.

Causes, incidence, and risk factors:

Neonatal conjunctivitis is most commonly caused by:

• A blocked tear duct
• Infection by bacteria or viruses, or irritation from antibiotic eyedrops called silver nitrate (these are rarely used anymore)

Neonatal conjunctivitis that is caused by an infection with bacteria or viruses can be very serious. The most common bacterial infections that can cause serious eye damage are gonorrhea (Neisseria gonorrhea) and chlamydia (Chlamydia trachomatis), which can be passed from mother to child during birth.

Bacteria that normally live in a woman's vagina also cause neonatal conjunctivitis.

The viruses that cause genital and oral herpes may also be passed to the baby during childbirth, leading to neonatal conjunctivitis and severe eye damage. However, herpes conjunctivitis is less common than conjunctivitis caused by gonorrhea and chlamydia.

The mother may be without symptoms (asymptomatic) at the time of delivery, yet still carry bacteria or viruses that can cause conjunctivitis in the newborn.