Viral conjunctivitis

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Viral conjunctivitis is the most common form of infectious conjunctivitis and is usually caused by adenoviruses. Patients present with clinical features of conjunctivitis, including conjunctival injection, watery discharge, and preauricular lymphadenopathy. Associated clinical features (e.g., vesicular rash, history of upper respiratory tract infection) may help determine the etiology. Diagnostic studies are typically not needed to start management. Treatment is usually supportive, but patients with varicella-zoster conjunctivitis or herpes simplex conjunctivitis (HSV conjunctivitis) are at increased risk of keratitis and should be referred to ophthalmology for management, including antivirals. Prevention measures are advised to limit the spread of infection.

• Most common type of conjunctivitis (∼ 80% of cases) ^[2]
• Incidence increases during the winter. ^[3]

Epidemiological data refers to the US, unless otherwise specified.

• Adenoviruses (most common; ; highly contagious)
• Herpes simplex virus (HSV)
• Varicella-zoster virus (VZV)
• Molluscum contagiosum virus
• SARS-CoV-2
• Measles virus
• Picornaviruses, e.g., coxsackievirus and enterovirus ^[5]

• Clinical features of conjunctivitis include: ^[2]
  • Conjunctival injection
  • Chemosis
  • Watery discharge
  • Preauricular lymphadenopathy
• Additional clinical features depend on the underlying etiology and include:
  • History of an upper respiratory tract infection (URTI) in adenovirus conjunctivitis ^[3]
  • Vesicular lesions in HSV conjunctivitis and varicella-zoster conjunctivitis

• Viral conjunctivitis is usually a clinical diagnosis. ^[4]
• If there is diagnostic uncertainty between viral and bacterial conjunctivitis, consider : ^[4]
  • Conjunctival swab for culture and staining (see “Diagnostics for bacterial conjunctivitis”)
  • Viral diagnostic tests, e.g.: ^[6]
    • PCR (preferred)
    • Rapid antigen testing
    • Viral culture
    • Serology for IgM

• Provide supportive therapy for conjunctivitis. ^[4]
• Start tailored treatment if necessary, e.g., topical antiviral therapy for HSV conjunctivitis.
• Refer to ophthalmology for any of the following: ^[2][4][7]
  • Suspected HSV conjunctivitis or herpes zoster ophthalmicus
  • Symptoms that persist for 7–10 days or longer
  • Red flag features of conjunctivitis
• Educate patients on preventive measures against infectious conjunctivitis.

Viral conjunctivitis is usually self-limited and only requires supportive therapy. ^[8]

The most common cause of viral conjunctivitis; clinical presentations vary depending on the subtype. Management for all presentations is supportive.

Etiology

• Caused by Adenoviridae spp.
• Multiple subtypes affect humans and can cause different clinical presentations. ^[3][9]

Transmission ^[3][9]

• Direct contact (eye, respiratory secretions)
• Fecal-oral route
• Contamination via:
  • Objects (e.g., door handles)
  • Water (e.g., from swimming pools)
• Nosocomial infection

Clinical features ^[6]

There are four presentations of adenovirus conjunctivitis. In addition to conjunctivitis symptoms, patients may have had a preceding URTI.

Epidemic keratoconjunctivitis ^[2][4][6]

• Acute phase (typically 7–21 days) ^[9]
  • Sudden onset
  • Preauricular lymphadenopathy
  • Tarsal conjunctival follicles ^[3]
  • Subconjunctival and petechial hemorrhage
  • Epithelial keratitis
  • Development of membranes or pseudomembranes on the conjunctiva ^[6]
• Chronic phase
  • Corneal involvement ^[9]
  • Symblepharon ^[6]
  • Tarsal scarring ^[6]
  • Visual impairment

Pharyngoconjunctivitis ^[2][4]

• Sudden onset of high fever
• Pharyngitis
• Acute follicular conjunctivitis (unilateral or bilateral)
• Tender preauricular lymphadenopathy

Acute nonspecific follicular conjunctivitis ^[6]

• Mild conjunctivitis with conjunctival injection, mild pain, and lacrimation
• Tarsal follicles
• No corneal involvement

Chronic adenovirus conjunctivitis ^[6]

• Recurrent episodes of conjunctival injection, lacrimation, and photophobia
• Conjunctival papillae predominate as opposed to follicles
• Patients typically have a history of viral conjunctivitis in the previous 6–9 months.

Diagnostics

• Primarily a clinical diagnosis ^[2][4]
• A rapid antigen test is available; consider if there is diagnostic uncertainty, to avoid unnecessary antibiotic use. ^[6]
• Other confirmatory tests include: ^[3][4]
  • PCR
  • Enzyme immunoassay
  • Viral culture
  • Raman spectroscopy (of tears)
  • Assessment of hyaluronic acid levels in tears

Treatment ^[2][4][7]

• Symptomatic therapy may include: ^[4]
  • Supportive therapy for conjunctivitis (e.g., artificial tears, cold compresses)
  • Oral analgesics (e.g., NSAIDs)
  • Topical antihistamines for severe pruritus
  • Topical steroids to relieve symptoms and reduce long-term complications; discuss use with ophthalmology. ^[4][6]
• Refer patients to ophthalmology if they have: ^[4]
  • Severe disease with either:
    • Corneal epithelial ulceration
    • Membranous conjunctivitis
  • Vision changes
  • Ongoing symptoms after 2–3 weeks of supportive treatment
• Educate patients on preventive measures against infectious conjunctivitis; adenovirus conjunctivitis is highly infectious. ^[4]

Adenovirus conjunctivitis and HSV conjunctivitis can manifest very similarly; use topical steroids with extreme caution as steroids worsen HSV disease. ^[10]

HSV conjunctivitis is usually caused by subtype HSV-1; it is transmitted through close contact and inoculates the conjunctiva. In neonates, HSV can cause severe symptoms; for diagnosis and management see “Neonatal HSV conjunctivitis.” ^[11]

Clinical features ^[4]

• Typically unilateral
• Thin, watery discharge
• Pain
• Vesicular blepharitis
• Dendritic epithelial keratitis of cornea or conjunctiva
• May be accompanied by:
  • Preauricular lymphadenopathy
  • Ulcer(s) or vesicular rash on the eyelid
• Potential sequelae: corneal endotheliitis, trabeculitis, or uveitis

HSV conjunctivitis may manifest without a periocular rash; in these cases, it may be hard to distinguish from other forms of viral conjunctivitis, e.g., adenovirus conjunctivitis. ^[10]

Diagnostics

• Primarily a clinical diagnosis
• Consider viral studies (e.g., enzyme immunoassay, PCR, viral cultures) if there is diagnostic uncertainty or to evaluate for antiviral susceptibilities. ^[4][11]

Treatment ^[4]

• Provide supportive treatment of conjunctivitis.
• Start topical antivirals, e.g.:
  • Ganciclovir (off-label) ^[4]
  • OR trifluridine (off-label) ^[4]
• Suspected HSV keratitis: Give oral antivirals in addition to topical antivirals.
  • Acyclovir (off-label) ^[4]
  • OR valacyclovir (off-label) ^[4]
  • OR famciclovir (off-label)
• Educate patients on preventive measures against infectious conjunctivitis.

Topical steroids can worsen HSV infection and should be avoided. ^[4]

Long-term suppressive antiviral therapy may decrease the risk of recurrent HSV keratitis. ^[4]

Conjunctivitis is one of the ocular manifestations of varicella-zoster infection; other manifestations include keratitis and retinitis.

Etiology ^[4]

• Caused by varicella-zoster virus
• Ocular involvement can occur during:
  • Primary varicella infection (chickenpox)
  • Reactivation of varicella (see “Herpes zoster ophthalmicus”)

Clinical features ^[4]

• Classic clinical features of conjunctivitis
• Concomitant punctate keratitis
• Preauricular lymphadenopathy may be present.
• In primary zoster infection
  • Widespread vesicular rash
  • Lesions may form on the conjunctiva and limbus.
• In herpes zoster ophthalmicus
  • Vesicular lesions in a dermatomal distribution on the face
  • In addition to punctate keratitis, dendritic keratitis may be present
• Features of secondary bacterial infection (e.g., mucopurulent discharge) may be present.

A delay in treatment may lead to vision loss in patients with concomitant herpes zoster keratitis. ^[12]

Diagnostics ^[13]

• Typically a clinical diagnosis
• Confirmatory diagnostic tests (e.g., PCR, culture) are usually not required.
• For further information, see “Diagnostics” in “Chickenpox” and “Shingles.”

Treatment ^[4]

• Patients with isolated conjunctivitis
  • Provide supportive therapy for conjunctivitis.
  • Start topical antibiotic therapy for acute bacterial conjunctivitis to prevent secondary bacterial infection.
• Patients with suspected concomitant keratitis
  • Start oral antiviral therapy.
    • Herpes zoster: Initiate antiviral therapy for herpes zoster.
    • Primary varicella infection: Initiate antiviral therapy for chickenpox.
  • Refer to an ophthalmologist for evaluation.

Isolated varicella-zoster conjunctivitis is usually self-limited. ^[4]

Prevention ^[4]

• Educate patients on preventive measures against infectious conjunctivitis.
• Nonimmune close contacts may require postexposure prophylaxis for chickenpox.
• Encourage patients to keep up-to-date on vaccinations, including:
  • Chickenpox immunization
  • Shingles immunization

Molluscum contagiosum conjunctivitis can occur when lesions on the eyelid shed virus onto the conjunctiva.

Etiology ^[4]

• Molluscum contagiosum virus (Poxviridae)
• Risk factors include lesions close to the eye.

Clinical features ^[4]

• Common findings
  • Unilateral conjunctivitis
  • Follicular conjunctivitis
  • Lesion(s) on the eyelid with central umbilication
  • Punctate epithelial keratitis
• Long-term infection
  • Corneal pannus
  • Conjunctival scarring

Multiple lesions or large lesions suggest underlying immunodeficiency. ^[4]

Diagnostics

• Usually clinical
• Consider further studies if there is diagnostic uncertainty or an underlying immunodeficiency is suspected.
• See “Diagnostics of molluscum contagiosum” for further information.

Treatment ^[4]

• Provide supportive therapy for conjunctivitis.
• Removal of eyelid lesions reduces viral shedding to the eye and is indicated for symptomatic patients; options include : ^[4][14]
  • Incision and curettage
  • Punch biopsy
  • Cryotherapy
• Refer to a dermatologist if an alternative cause (e.g., neoplasm) is suspected. ^[4]

Epidemiology ^[15]

• Affects both adults and children ^[16]
• Prevalence rates are unclear but vary between 1% and 32% in studies. ^[15]

Clinical features ^[15]

• Usually classic clinical features of conjunctivitis.
• May be the first presentation of COVID-19 infection ^[15]
• May be accompanied by:
  • Other clinical features of COVID-19
  • Symptoms of multisystem inflammatory syndrome in children (MIS-C) ^[16]

Diagnosis ^[15]

• Perform viral testing for COVID-19 to confirm the diagnosis.
• Suspected MIS-C: Send CBC, CMP, and inflammatory markers. ^[17]

Treatment ^[18]

• Typically self-limited
• Provide supportive therapy for conjunctivitis.

Prevention ^[19]

• Advise patients to take preventive measures against infectious conjunctivitis.
• Educate patients on COVID-19 preventive measures.