Excerpt from Conjunctivitis, Viral

Synonyms, Key Words, and Related Terms: viral conjunctivitis, conjunctival infection, adenovirus, adenoviral conjunctivitis, epidemic keratoconjunctivitis, pinkeye, pink eye, pharyngoconjunctival fever, herpes simplex virus, HSV, ocular herpes simplex infection, follicular conjunctivitis, varicella-zoster virus, VZV, picornavirus, enterovirus 70, Coxsackie A24, hemorrhagic conjunctivitis, poxvirus, molluscum contagiosum, vaccinia, human immunodeficiency virus, HIV

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Background: Viruses are a common cause of conjunctivitis in patients of all ages. A variety of viruses can be responsible for conjunctival infection; however, adenovirus is by far the most common cause, and herpes simplex virus (HSV) is the most problematic. Less common causes include varicella-zoster virus (VZV), picornavirus (enterovirus 70, Coxsackie A24), poxvirus (molluscum contagiosum, vaccinia), and human immunodeficiency virus (HIV). Rarely, conjunctivitis is seen during systemic infection with influenza virus, Epstein-Barr virus, paramyxovirus (measles, mumps, Newcastle), and rubella.

Viral conjunctivitis, although usually benign and self-limited, tends to follow a longer course than acute bacterial conjunctivitis, lasting for approximately 2-4 weeks. Viral infection is characterized commonly by an acute follicular conjunctival reaction and preauricular adenopathy.

Pathophysiology: Adenoviral conjunctivitis is the most common cause of viral conjunctivitis. Particular subtypes of adenoviral conjunctivitis include epidemic keratoconjunctivitis (pink eye) and pharyngoconjunctival fever. Transmission occurs through contact with infected upper respiratory droplets, fomites, and contaminated swimming pools.

Primary ocular herpes simplex infection is common in children and usually is associated with a follicular conjunctivitis. Infection usually is caused by HSV type I, although HSV type II may be a cause, especially in neonates. Recurrent infection, typically seen in adults, usually is associated with corneal involvement.

VZV can affect the conjunctiva during primary infection (chickenpox) or secondary infection (zoster). Infection can be caused by direct contact with VZV or zoster skin lesions or by inhalation of infectious respiratory secretions.

Picornaviruses cause an acute hemorrhagic conjunctivitis that is clinically similar to adenoviral conjunctivitis but is more severe and hemorrhagic. Infection is highly contagious and occurs in epidemics.

Molluscum contagiosum may produce a chronic follicular conjunctivitis that occurs secondary to shedding of viral particles into the conjunctival sac from an irritative eyelid lesion.

Vaccinia virus has become a rare cause of conjunctivitis because with the elimination of smallpox, the vaccination rarely is administered. Infection occurs through accidental inoculation of viral particles from the patient’s hands.

HIV is the etiologic agent of acquired immunodeficiency syndrome (AIDS). Ocular abnormalities in patients with AIDS primarily affect the posterior segment, but anterior segment findings have been reported. When conjunctivitis occurs in a patient with AIDS, it tends to follow a more severe and prolonged course than in patients without AIDS. In general, patients with AIDS may develop a transient nonspecific conjunctivitis, characterized by irritation, hyperemia, and tearing, that requires no specific treatment. Microsporidia has been isolated from the cornea and conjunctiva of several patients with AIDS and keratoconjunctivitis. In these patients, symptoms included foreign body sensation, blurred vision, and photophobia; most cases resolved without antimicrobial therapy.

Frequency:

In the US: Viral conjunctivitis is a common ocular disease both in the United States and worldwide. Because it is so common, and many cases are not brought to medical attention, accurate statistics on the frequency of disease are unavailable. Viral infection frequently occurs in epidemics within families, schools, offices, and military organizations.

Internationally: Same as in the United States.

Mortality/Morbidity: Most cases of viral conjunctivitis are self-limited and mild, although chronic infections have been reported. Long-term ocular sequelae are uncommon.

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