Viral conjunctivitis: types, symptoms and treatment tactics

Viral conjunctivitis is an acute inflammation of the conjunctiva caused by viral agents, most commonly adenoviruses, and less commonly by herpes simplex viruses, varicella-zoster viruses, enteroviruses, and coxsackieviruses. Classic manifestations include redness, watery discharge, itching, and a foreign body sensation. Both eyes are typically affected, but onset may be unilateral, with the other eye subsequently becoming involved within 2-3 days. The disease is highly contagious and spreads easily within families, groups, and healthcare facilities. [1]

Clinical forms vary in severity. The most severe is epidemic keratoconjunctivitis, which causes long-term corneal opacities and persistent photophobia. Less severe forms, such as pharyngoconjunctival fever, are accompanied by systemic symptoms, including fever and sore throat. Of particular epidemiological significance is acute hemorrhagic conjunctivitis caused by enteroviruses and coxsackieviruses, which is characterized by outbreaks in tropical and subtropical regions. [2]

It's important to understand that antibacterial drops do not cure viral conjunctivitis. Self-medication with decongestants temporarily reduces redness, but does not affect inflammation and may worsen hyperemia with prolonged use. Current guidelines emphasize supportive care, strict hygiene and infection control, and accurate identification of herpes infections requiring antiviral treatment. [3]

Recovery times vary. Non-herpetic viral conjunctivitis typically resolves within 7-14 days, although symptoms may persist longer if the cornea is affected. Herpetic lesions, especially those involving the cornea, require special management and specialist supervision. [4]

Code according to ICD 10 and ICD 11

Viral conjunctivitis is conveniently coded in the International Classification of Diseases, Tenth Revision, under the section "Viral conjunctivitis" with entries B30. For epidemic keratoconjunctivitis, the code "keratoconjunctivitis due to adenovirus" is used, while for pharyngoconjunctival fever and other adenoviral forms, the corresponding sections are used. If necessary, codes from section H10 can be used to clarify the severity and morphology of conjunctivitis; however, these entries do not indicate the etiology. [5]

In the International Classification of Diseases, Eleventh Revision, viral and other conjunctivitis are grouped into block 9A60 "Conjunctivitis" with subtypes based on clinical and morphological features. For epidemic keratoconjunctivitis and other adenoviral forms, the "conjunctivitis" category is used; corneal involvement and the nature of the lesion are indicated when necessary. The current version of the classifier should be used, as the list of clarifying items is updated. [6]

Table 1. Frequently used International Classification of Diseases codes

System	Code	Name
ICD 10	B30.0	Keratoconjunctivitis due to adenovirus (epidemic keratoconjunctivitis)
ICD 10	B30.1	Conjunctivitis due to adenovirus
ICD 10	B30.2	Viral pharyngoconjunctival fever
ICD 10	B30.3	Acute epidemic hemorrhagic conjunctivitis
ICD 11	9A60	Conjunctivitis (specific subtypes based on morphology and course)
[7]

Epidemiology

Viral conjunctivitis is the most common cause of infectious conjunctivitis in adults, while bacterial etiologies are more common in children. Adenoviruses predominate among the pathogens, accounting for a significant proportion of outbreaks in communities and healthcare facilities. The risk of outbreaks is particularly high in ophthalmology clinics where equipment disinfection measures are not followed. [8]

Epidemic keratoconjunctivitis is highly contagious and can cause large epidemics. The Centers for Disease Control and Prevention (CDC) recommends disinfecting not only surfaces but also ophthalmic equipment, which is critical for preventing nosocomial spread. Outbreaks can last for weeks due to prolonged viral shedding. [9]

Acute hemorrhagic conjunctivitis is reported in outbreaks in tropical and subtropical countries. The most common agents are enterovirus 70 and coxsackievirus A24 variant. The disease is highly contagious but usually benign and resolves within 5-7 days; however, rare neurological complications have been described for enterovirus 70. [10]

Viral conjunctivitis often correlates with periods of increased respiratory virus circulation. Adenoviral forms are often accompanied by fever and sore throat, while herpetic lesions are more often unilateral and involve the skin of the eyelids. These characteristics are taken into account during clinical evaluation. [11]

Table 2. Epidemiological landmarks

Indicator	Characteristic
Adults	Viral etiology predominates
Children	Bacterial etiology is more common
Epidemic keratoconjunctivitis	Highly contagious outbreaks, including in clinics
Acute hemorrhagic conjunctivitis	Outbreaks in the tropics, highly contagious
[12]

Reasons

The main pathogens are adenoviruses, which cause a wide range of ocular symptoms, from catarrhal conjunctivitis to severe keratitis with subepithelial infiltrates. The virus is excreted in tears and secretions, as well as in respiratory secretions, which explains the association with cold symptoms and easy transmission by contact. A number of serotypes exhibit increased resistance in the environment. [13]

Herpes viruses cause unilateral forms with a risk of corneal damage. Herpes simplex virus most often produces epithelial defects with typical dendrites, while herpes zoster virus is accompanied by a rash along the branches of the trigeminal nerve and severe inflammation. These forms require systemic or local antiviral therapy. [14]

Picornaviruses, including enterovirus 70 and coxsackievirus A24 variant, cause acute hemorrhagic conjunctivitis. It is characterized by rapid onset, severe pain, subconjunctival hemorrhages, and extreme contagiousness. Despite the dramatic presentation, the course is usually self-limited. [15]

Viral conjunctivitis can accompany respiratory infections and spread through contaminated hands, personal hygiene items, and medical instruments. Therefore, hygiene measures are key to prevention and breaking the chain of transmission both in the home and in the clinic. [16]

Risk factors

Close contact with infected individuals and poor hand hygiene are the main risk factors. Infections can spread quickly in family settings, childcare facilities, and closed groups, especially when sharing towels, cosmetics, or contact lenses. Outbreaks in healthcare facilities are associated with inadequate equipment disinfection. [17]

Wearing contact lenses does not in itself cause viral conjunctivitis, but it does contribute to more severe discomfort and the risk of secondary corneal problems in the presence of existing inflammation. During respiratory virus season, lens tolerance may be impaired by tearing and irritation. [18]

A weakened immune system and chronic atopic skin and eye diseases increase the risk of severe shingles, especially if the condition is herpetic. Patients with diabetes and the elderly are more likely to experience severe shingles with ocular manifestations. [19]

Behavioral habits such as rubbing the eyes, using decongestant drops instead of treatment, and delaying medical attention prolong the course of the illness and increase the risk of infecting others. Patient education reduces the spread of infection and speeds recovery. [20]

Table 3. Risk factors and context

Factor	Context
Close household contacts	Rapid transmission in the family, school, kindergarten
Medical environment	Risk of insufficient disinfection of equipment
Contact lenses	Increased discomfort and irritation with inflammation
Immunodeficiency, old age	Severe course of herpetic forms
[21]

Pathogenesis

Adenoviral forms are characterized by a cytopathic effect on the conjunctival and corneal epithelium, activation of the innate immune system, and subsequent tissue infiltration with inflammatory cells. In epidemic keratoconjunctivitis, subepithelial corneal infiltrates often form, causing prolonged photophobia and blurred vision. These infiltrates are immune-mediated and can persist for weeks. [22]

Herpes viruses penetrate and replicate in the epithelium, causing characteristic dendritic erosions. The immune response, including cellular mechanisms, determines the clinical picture and the risk of relapse. In herpes zoster, the neurodermatotropic nature of the virus explains the combination of skin rash and ocular inflammation, as well as severe pain. [23]

In acute hemorrhagic forms, picornaviruses cause a pronounced vascular reaction and subconjunctival hemorrhages. The high viral load in the first days of illness explains the rapid spread and pronounced clinical picture. Despite the intensity of symptoms, the damage is usually reversible. [24]

The persistence of viruses in the environment and their prolonged excretion in tears maintain the chain of transmission. This underscores the importance of infection control, including disinfection of slit lamps, tonometers, and accessories, as well as strict hand hygiene at home. [25]

Symptoms

Typical complaints include redness, lacrimation, a gritty sensation, moderate photophobia, and itching. Muco-watery discharge predominates over purulent discharge. Many patients experience systemic signs of a respiratory infection, including sore throat, fever, and weakness. The onset is often acute. [26]

Adenoviral forms are often accompanied by pain and swelling of the preauricular lymph nodes. In epidemic keratoconjunctivitis, subepithelial infiltrates of the cornea may develop within 7-10 days, increasing photophobia and clouding. These symptoms may persist after the conjunctival phase subsides. [27]

Herpetic forms are often unilateral and are accompanied by pain, severe photophobia, and decreased visual acuity when the cornea is involved. In herpes zoster, skin vesicular eruptions corresponding to the dermatome are also present. This combination helps quickly differentiate the nature of the process. [28]

Acute hemorrhagic conjunctivitis presents with sudden, severe pain, lacrimation, and bright subconjunctival hemorrhages. Vision is usually not permanently affected, but pain and photophobia can make patients unable to work in the first few days. [29]

Table 4. The most common symptoms and signs

Symptom or sign	Viral conjunctivitis
Watery or mucous discharge	Typically
Preauricular lymphadenia	Often with adenovirus infection
One-sided start	Often with herpetic forms
Subconjunctival hemorrhages	Characteristic of the hemorrhagic form
[30]

Classification, forms and stages

Based on etiology, adenoviral, herpetic, and picornaviral forms are distinguished. Severity is classified as mild, moderate, and severe, with corneal involvement. Based on clinical syndromes, pharyngoconjunctival fever and epidemic keratoconjunctivitis are traditionally distinguished among adenoviral variants. [31]

The course of the disease is divided into an early catarrhal phase with a predominance of conjunctival symptoms and a late phase with epidemic keratoconjunctivitis with the formation of subepithelial infiltrates of the cornea. This division is convenient for planning observation and choosing treatment tactics. [32]

Herpetic forms are divided into those caused by the herpes simplex virus and those caused by the herpes zoster virus. The former is more characterized by epithelial defects, while the latter is associated with a skin rash and neurogenic pain. This distinction is critical for the selection of antiviral regimens. [33]

Acute hemorrhagic conjunctivitis is classified as a separate group due to its epidemiological significance and clinical presentation with severe hemorrhages. In most cases, the course is self-limited, and specific therapy is not required. [34]

Complications and consequences

The main problem with adenoviral infection is subepithelial infiltrates of the cornea. These cause photophobia, blurred vision, and can persist for weeks. Anti-inflammatory courses under the supervision of an ophthalmologist are sometimes required to control them. Unsupervised use of hormonal eye drops is dangerous. [35]

Herpetic corneal lesions carry the risk of persistent opacities and decreased vision. Incorrect or untimely administration of corticosteroids during active epithelial lesions worsens the prognosis. Timely antiviral treatment reduces the risk of relapse and complications. [36]

Neurological complications have rarely been reported in acute hemorrhagic conjunctivitis following enterovirus 70 infection. Despite the low incidence, this highlights the need for sanitary and anti-epidemic measures during outbreaks. [37]

Indirect consequences include long-term disability, reduced quality of life, and the need for restrictions in daily life and work to prevent the spread of infection. Effective patient education reduces these consequences. [38]

When to see a doctor

Any acute eye redness with watery discharge requires a medical evaluation, especially if accompanied by systemic cold symptoms or a sore throat. A doctor will confirm a viral cause, provide infection control recommendations, and rule out dangerous conditions. Self-medication without a diagnosis increases the risk of complications and the spread of infection. [39]

Urgent treatment is required in cases of severe pain, severe photophobia, noticeable decrease in visual acuity, profuse purulent discharge, eye injury, or contact lens wear with pain. These symptoms are atypical for simple viral conjunctivitis and require the exclusion of keratitis or other urgent conditions. [40]

Do not delay a visit if you have severe, unilateral inflammation with a skin rash on the forehead and nose or blisters on the eyelids, which is typical of herpes zoster. These cases require specific antiviral therapy and monitoring. [41]

If symptoms persist for more than 14 days, if there is a clear deterioration after a period of improvement, or if there are relapses, a repeat examination is necessary. Further diagnostic workup and adjustment of therapy may be necessary. [42]

Table 5. Red flags and recommended actions

Sign	Possible cause	Action
Severe pain, severe photophobia, decreased vision	Corneal lesion	See an ophthalmologist urgently
Unilateral lesion with skin rash along the dermatome	Shingles	Immediately start systemic antiviral drugs as prescribed by your doctor
Purulent discharge, sticking of eyelashes	Bacterial infection	Examination, etiotropic therapy
Duration more than 14 days or relapses	Complicated course	Re-evaluation and adjustment of tactics
[43]

Diagnostics

The first step is a clinical assessment: contact history, onset in one eye, presence of systemic symptoms, contact lens use, and associated skin manifestations. Examination includes a slit lamp to assess the conjunctiva, cornea, and discharge, and palpation of the preauricular lymph nodes. In typical cases, this is sufficient for diagnosis. [44]

The second step is determining the need for testing. In outbreaks, severe cases, atypical presentations, or for infection control management, rapid adenovirus tests and polymerase chain reaction (PCR) can be used. Rapid immunoassays have high specificity and variable sensitivity; a negative test does not rule out adenovirus. PCR remains the standard. [45]

The third step is to rule out herpes-related causes. If herpes simplex virus or shingles is suspected, early antiviral therapy is indicated. Polymerase chain reaction (PCR) can be used for confirmation, but in practice, the decision is often made clinically to avoid wasting time. [46]

The fourth step is an assessment of associated factors: contact lenses, dry eyes, and allergies. These factors influence the severity of symptoms and the choice of topical treatment. If a bacterial cause and purulent discharge are suspected, appropriate adjustments are made to the treatment plan. [47]

Table 6. Diagnostic tools and their properties

Method	Purpose	Peculiarities
Clinical examination	Basic verification	Sufficient in typical cases
Rapid test for adenovirus	Confirmation of etiology, especially in outbreaks	High specificity, variable sensitivity
Polymerase chain reaction	The gold standard for adenovirus	Limited availability, useful for flare-ups
Herpes tests	Confirmation when in doubt	Treatment tactics are often clinical
[48]

Differential diagnosis

Bacterial conjunctivitis often produces purulent discharge and sticky eyelashes in the morning. It is less contagious and usually resolves spontaneously within 5-10 days; antibiotics are prescribed selectively. Viral forms produce watery discharge and are often accompanied by preauricular lymphadenopathy. [49]

Allergic conjunctivitis is characterized by severe itching, recurs upon contact with an allergen, and is often associated with rhinitis. Discharge is usually mucous and clear; pus and pain are uncommon. Improvement with antihistamine drops and mast cell stabilizers supports the diagnosis. [50]

Dry eye syndrome mimics a burning and gritty sensation, but lacks the typical seasonal viral dynamics. Objective tests of tear film stability and osmolarity help differentiate. Combined conditions require individualized therapy. [51]

Serious causes of "red eye," including keratitis, uveitis, and acute angle-closure attack, are accompanied by severe pain, photophobia, and decreased vision and require emergency care. These conditions should be ruled out in any patient with severe symptoms. [52]

Table 7. Differences in common conditions

State	Discharge	Itching	Pain	Lymph nodes	Cornea
Viral conjunctivitis	Watery/mucous	Moderate	Moderate	Often pre-auricular	Infiltrates are possible in epidemic keratoconjunctivitis
Bacterial conjunctivitis	Purulent	Weak	Moderate	Rarely	Usually intact
Allergic conjunctivitis	Mucous membranes	Expressed	No	No	Intact
Keratitis/uveitis	Different	No	Strong	No	Often affected
[53]

Treatment

The first principle is supportive care and infection control. Cold compresses, preservative-free artificial tears, eyelid hygiene, and avoiding eye rubbing are recommended. Patients are instructed in frequent hand washing, individual towels, and temporary isolation from childcare facilities and close contacts during the infectious period. [54]

Decongestant drops do not treat inflammation and, with prolonged use, can cause rebound hyperemia. Their use should be avoided or limited to short courses in exceptional cases. When symptomatic relief of itching is needed, mild antihistamine drops are preferable. [55]

Antibacterial drops are not indicated for typical viral conjunctivitis. Their unjustified use does not speed recovery and increases the risk of side effects. The exception is documented bacterial infection, as determined by the clinician and the physician. [56]

Ophthalmic use of povidone-iodine is being studied to reduce viral load and symptoms in adenoviral conjunctivitis. Systematic reviews suggest that a single treatment and repeated instillations may accelerate recovery, but the evidence base is limited and inconsistent. The decision should be made by an ophthalmologist, taking into account tolerability. [57]

Topical corticosteroids are not recommended for uncomplicated adenoviral infections due to the risk of prolonged viral shedding and adverse effects. An exception is severe keratitis with subepithelial infiltrates, in which case an ophthalmologist may prescribe a short course with careful monitoring of intraocular pressure and subsequent dose reduction. [58]

Herpetic conjunctivitis and keratitis require antiviral therapy. For herpes simplex virus, topical ganciclovir gel and systemic antiviral agents based on acyclovir, valacyclovir, or famciclovir are used. During the active epithelial lesion phase, topical hormones are contraindicated. [59]

For herpes zoster with ocular manifestations, the standard treatment is early initiation of systemic antiviral drugs, sometimes with the addition of topical corticosteroids at the discretion of a specialist. Early initiation of therapy reduces the risk of ophthalmologic complications and postherpetic neuralgia. [60]

Acute hemorrhagic conjunctivitis is treated supportively; there are no specific antiviral drugs. Key measures include pain relief, cold compresses, artificial tears, and strict infection control measures. The disease is self-limiting within 5-7 days. [61]

The role of rapid adenovirus testing is to streamline clinical management and reduce unnecessary antibiotic prescriptions. A positive result strengthens the diagnosis, while a negative result does not rule out adenovirus infection given the low sensitivity of individual tests, and the clinical decision remains with the physician. [62]

Patients wearing contact lenses are advised to temporarily switch to glasses during the period of symptoms and for 24-48 hours after their disappearance. Containers and solutions should be replaced, and the lenses themselves, in some cases, should be disposed of to prevent re-infection. [63]

Table 8. Main treatment options

Direction	Examples	Comments
Supportive therapy	Cold compresses, artificial tears without preservatives	Help base, safe
Antiviral drugs for herpes forms	Acyclovir, valacyclovir, ganciclovir gel	Start early, steroids are contraindicated in epithelial lesions
Povidone-iodine for adenovirus	One-time washes and/or courses as determined by the doctor	Efficacy data are limited.
Corticosteroids	Only for keratitis with infiltrates and under control	Risk of delayed viral clearance
[64]

Prevention

Hand hygiene, using individual towels, and avoiding eye contact are simple but effective measures. During illness, visits to schools, daycare centers, and crowded places should be limited. In the home, it is important to regularly disinfect frequently touched surfaces and objects. [65]

Medical facilities require disinfection protocols for ophthalmological equipment, including tonometers and slit lamp accessories. Failure to comply with these requirements has led to outbreaks of epidemic keratoconjunctivitis. Personnel should be trained in standard precautions. [66]

For patients with herpes recurrences, discussion of shingles vaccination and early treatment strategies at the first sign of symptoms may be helpful. Contact lenses should be used strictly according to care and hygiene guidelines, especially during the respiratory infection season. [67]

Information leaflets with brief rules help reduce household and hospital-acquired transmission. A simple family roadmap with a list of actions increases compliance and reduces the duration of outbreaks in groups. [68]

Table 9. Infection control at home and in the clinic

Wednesday	Key actions
House	Frequent hand washing, individual towels, wiping down surfaces, no shared cosmetics
Educational institutions	Temporary isolation of sick people, informing parents and staff
Clinic	Disinfection of equipment and accessories, monitoring of common surfaces, staff training
[69]

Forecast

Most non-herpetic viral conjunctivitis cases are self-limited within 1-2 weeks. With proper hygiene and supportive care, symptoms quickly subside, and complications are rare. Pain and photophobia can be controlled with simple steps. [70]

Epidemic keratoconjunctivitis can leave subepithelial infiltrates, causing photophobia and blurred vision to persist. This condition is reversible but sometimes requires anti-inflammatory therapy as prescribed by an ophthalmologist. The prognosis is favorable with proper management. [71]

Herpetic forms are more dangerous for the cornea. Timely initiation of antiviral medications improves outcomes and reduces the risk of persistent opacities. Recurrences can be prevented and treated with regular monitoring. [72]

Educational measures reduce transmission and improve patient satisfaction. For recurrent episodes, it is helpful to have a pre-agreed action plan, including testing as indicated and prompt communication with a specialist. [73]

Frequently asked questions

Are antibiotics necessary for viral conjunctivitis?
No. Antibacterial drops do not treat viral infections and are prescribed only when a bacterial infection is clinically confirmed. [74]

How long is a person contagious?
Contagiousness is high during the first 7-10 days of the adenovirus form. Strict hand hygiene should be observed and personal hygiene items should not be shared to avoid infecting others. [75]

What to do with contact lenses?
During symptomatic periods, switch to glasses, replace containers and solutions, and, in some cases, dispose of lenses. Resuming contact lens use is possible 24-48 hours after symptoms resolve. [76]

Do hormonal drops help?
For simple adenoviral conjunctivitis, no, and they can prolong viral shedding. The exception is severe corneal infiltrates, as determined by an ophthalmologist and under close supervision. Hormones are contraindicated for herpetic epithelial lesions. [77]

Are there any "antiviral drops" for adenovirus?
There are none specifically approved; ophthalmic treatment with povidone-iodine and supportive therapy are being discussed. Data on efficacy are limited, and the decision is individual. [78]