Conjunctivitis

INTRODUCTION — Conjunctivitis is a common diagnosis in patients who complain of a red eye. It is usually a benign or self-limited condition, or one that is easily treated. Other causes of red eye are discussed elsewhere. (See "The red eye: Evaluation and management".)

This topic will review the clinical manifestations, diagnosis, and treatment of conjunctivitis. Other conditions which may be confused with conjunctivitis include acute angle-closure glaucoma, iritis, uveitis, and infectious keratitis. In contrast to acute conjunctivitis, these conditions are sight-threatening and must be managed by an ophthalmologist. They are discussed elsewhere:

●(See "Angle-closure glaucoma".)

●(See "Uveitis: Etiology, clinical manifestations, and diagnosis" and "Uveitis: Treatment".)

●(See "Herpes simplex keratitis".)

●(See "Complications of contact lenses", section on 'Infectious keratitis'.)

Infectious conjunctivitis in the neonate is discussed separately. (See "Chlamydia trachomatis infections in the newborn" and "Gonococcal infection in the newborn".)

Ligneous conjunctivitis is discussed separately. (See "Plasminogen deficiency", section on 'Ligneous conjunctivitis'.)

DEFINITIONS AND ANATOMY — Conjunctivitis literally means "inflammation of the conjunctiva." The conjunctiva is the mucous membrane that lines the inside surface of the lids and covers the surface of the globe up to the limbus (the junction of the sclera and the cornea). The portion covering the globe is the "bulbar conjunctiva," and the portion lining the lids is the "tarsal conjunctiva" (figure 1).

The conjunctiva is comprised of an epithelium and a substantia propria. The epithelium is a non-keratinized squamous epithelium that also contains goblet cells. The substantia propria is highly vascularized and is the site of considerable immunologic activity.

The conjunctiva is generally transparent. When it is inflamed, as in conjunctivitis, it appears pink or red on general inspection. Up close, the examiner can discern fine blood vessels, termed "injection," in contrast to extravasated blood, which is seen in subconjunctival hemorrhage. All conjunctivitis is characterized by a red eye, but not all red eyes are conjunctivitis. (See "The red eye: Evaluation and management".)

CLASSIFICATION AND EPIDEMIOLOGY — Acute conjunctivitis can be classified as infectious (bacterial or viral) or noninfectious (allergic, toxic, or nonspecific). The prevalence of each type is different in pediatric and adult populations [1-3]. Bacterial conjunctivitis is more common in children, while viral is more common in adults [4].

CAUSES AND CLINICAL MANIFESTATIONS

Bacterial conjunctivitis

Common presentations — Patients with bacterial conjunctivitis typically complain of redness and discharge in one eye, although it can also be bilateral. Similar to viral and allergic conjunctivitis, the affected eye is often "stuck shut" in the morning [5]. The purulent discharge continues throughout the day and is thick and globular; it may be yellow, white, or green (picture 1). The discharge differs from that of viral or allergic conjunctivitis, which is mostly watery during the day, with a scant, stringy component that is mucus rather than pus. On examination, patients with bacterial conjunctivitis typically have purulent discharge at the lid margins and in the corners of the eye which reappears within minutes of wiping the lids. This contrasts with patients with viral or allergic conjunctivitis, in whom the eyes appear watery and where there may be mucus present on close inspection of the tear film or if one pulls down the lower lid, but pus does not appear spontaneously and continuously at the lid margin and in the corners of the eye (figure 2).

Bacterial conjunctivitis is commonly caused by Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. S. aureus infection is more common in adults; the other pathogens are more common in children [6].

Bacterial conjunctivitis is highly contagious and is spread by direct contact with the patient and their secretions or with contaminated objects and surfaces. Outbreaks due to S. pneumoniae have been described on college campuses and among military trainees [7,8].

Hyperacute bacterial conjunctivitis — Neisseria species, particularly N. gonorrhoeae, can cause a hyperacute bacterial conjunctivitis that is severe and sight-threatening, requiring immediate ophthalmologic referral (picture 2) [9]. The organism is usually transmitted from the genitalia to the hands and then to the eyes. Concurrent urethritis is typically present.

The eye infection is characterized by a profuse purulent discharge present within 12 hours of inoculation [10]; the amount of discharge is striking. Other symptoms are rapidly progressive and include redness, irritation, and tenderness to palpation. There is typically marked chemosis (conjunctival edema), lid swelling, and tender preauricular adenopathy. Conjunctival scrapings should be sent for immediate Gram stain to identify gram-negative diplococci. Polymerase chain reaction (PCR) can also be used for diagnosis of gonococcal conjunctivitis [11].

Chronic chlamydial infections

●Trachoma – Conjunctivitis is the major clinical manifestation of active trachoma, a chronic keratoconjunctivitis caused by recurrent infection with Chlamydia trachomatis. This disorder that is largely limited to endemic areas in less developed regions and is discussed separately. Active trachoma, which is most common in children and is typically asymptomatic, includes redness, discomfort, light sensitivity, and mucopurulent discharge. (See "Trachoma".)

●Adult inclusion conjunctivitis – Adult inclusion conjunctivitis is not strictly an acute conjunctivitis but rather a chronic, indolent conjunctivitis. It is a sexually transmitted infection (STI) caused by certain serotypes of C. trachomatis. Concurrent asymptomatic urogenital infection is typically present.

The eye infection presents as a unilateral, or sometimes bilateral, follicular conjunctivitis of weeks' to months' duration that has not responded to topical antibiotic therapy. There can be an associated keratitis. This diagnosis should be considered in chronic cases among populations at risk for STI.

Diagnosis is confirmed with Giemsa or direct fluorescent antibody (DFA) staining of conjunctival smears or by culture of swabbed specimens.

Viral conjunctivitis

Common presentations — Viral conjunctivitis is typically caused by adenovirus, with many serotypes implicated [12]. The conjunctivitis may be part of a viral prodrome followed by adenopathy, fever, pharyngitis, and upper respiratory tract infection, or the eye infection may be the only manifestation of the disease. Viral conjunctivitis is highly contagious; it is spread by direct contact with the patient and their secretions or with contaminated objects and surfaces [13]. Conjunctivitis can also be part of the prodrome or presentation of other viral upper respiratory tract infections.

Viral conjunctivitis typically presents as conjunctival injection with watery or mucoserous discharge (picture 3) and a burning, sandy, or gritty feeling in one eye. Patients may report "pus" in the eye, but on further questioning they have morning crusting followed by watery discharge, perhaps with some scant mucus throughout the day.

The second eye usually becomes involved within 24 to 48 hours, although unilateral signs and symptoms do not rule out a viral process. Patients often believe that they have a bacterial conjunctivitis that has spread to the fellow eye; they do not appreciate that this is the ocular manifestation of a systemic illness, even if they are experiencing viral symptoms at the same time (figure 2).

On examination there is typically only mucoid discharge if one pulls down the lower lid or looks very closely in the corner of the eye. Usually there is profuse tearing rather than discharge. The tarsal conjunctiva may have a follicular or "bumpy" appearance (picture 4). There may be an enlarged and tender preauricular node.

Viral conjunctivitis is a self-limited process. The clinical course parallels that of the common cold. While recovery can begin within days, the symptoms frequently get worse for the first three to five days, with very gradual resolution over the following one to two weeks for a total course of two to three weeks. Just as a patient with a cold can have morning coughing and nasal congestion or discharge two weeks after symptoms first arise, patients with viral conjunctivitis may have morning crusting two weeks after the initial symptoms, although the daytime redness, irritation, and tearing should be much improved.

Conjunctivitis might accompany herpes simplex virus (HSV) keratitis, acute varicella zoster (chickenpox), or herpes zoster ophthalmicus (V1 shingles), but the conjunctival process is self-limited, requiring no treatment beyond what would be undertaken for the herpes keratitis, for acute management of herpes zoster, or for management of chronic sequelae of herpes zoster ophthalmicus.

Epidemic keratoconjunctivitis — One form of viral conjunctivitis, epidemic keratoconjunctivitis (EKC), is particularly fulminant and causes a keratitis (inflammation of the cornea) that typically appears a few days after the initial conjunctivitis. It is typically caused by adenovirus types 8, 19, and 37 [14]. However, there is clinical variation; the same viral strain that causes EKC in one patient may cause ordinary viral conjunctivitis in another, probably due to differences in host immune factors. The corneal and conjunctival epithelium are both involved. In addition to the typical symptoms of viral conjunctivitis, the patient develops a foreign body sensation and multiple corneal infiltrates sometimes visible with a penlight (though easily seen at the slit lamp). The foreign body sensation is severe enough to preclude opening the eyes spontaneously, and the infiltrates typically degrade acuity by two or three lines to the 20/40 range.

Keratitis is potentially vision-threatening, and patients should be referred to an ophthalmologist to confirm the diagnosis and to decide whether a course of ophthalmic corticosteroids is warranted.

Allergic conjunctivitis — Allergic conjunctivitis is caused by airborne allergens contacting the eye that trigger a classic type I immunoglobulin E (IgE)-mediated hypersensitivity response specific to that allergen, causing local mast cell degranulation and the release of chemical mediators including histamine, eosinophil chemotactic factors, and platelet-activating factor, among others.

It typically presents as bilateral redness, watery discharge, and itching (picture 5). Itching is the cardinal symptom of allergy, distinguishing it from a viral etiology, which is more typically described as grittiness, burning, or irritation (figure 2). Eye rubbing can worsen symptoms. Patients with allergic conjunctivitis often have a history of atopy, seasonal allergy, or specific allergy (eg, to cats), and other allergic symptoms (eg, nasal congestion, sneezing, wheezing) may be present.

The clinical findings are the same as those seen in viral conjunctivitis (figure 2). Both cause diffuse injection with a bumpy or follicular appearance to the tarsal conjunctiva (picture 4). Some allergic conjunctivitis may present with larger papillary rather than follicular reaction. There is profuse watery or mucoserous, stringy discharge, and both may have morning crusting. It is the complaint of itching and the history of allergy or hay fever as well as a recent exposure that distinguishes allergic conjunctivitis.

In some cases of allergic conjunctivitis, there is marked chemosis (conjunctival edema); in extreme instances, there can be bullous chemosis, in which the bulging, edematous conjunctiva extends forward beyond the lid margins. Bullous chemosis is most commonly seen in patients with extreme hypersensitivity to cats. A detailed discussion of allergic disease is presented separately. (See "Allergic conjunctivitis: Clinical manifestations and diagnosis".)

Toxic conjunctivitis — Toxic conjunctivitis (also called toxic keratoconjunctivitis) is a chronic inflammation of the surface of the eye due to an offending agent, usually a preservative or medication. Toxic conjunctivitis is discussed in a separate topic. (See "Toxic conjunctivitis".)

Noninfectious, noninflammatory conjunctivitis — Patients can develop a red eye and discharge that is not related to either an infectious or inflammatory process. The discharge is more likely mucus than pus. Usually the cause is a transient mechanical or chemical insult. All of these generally improve spontaneously within 24 hours.

●Patients with dry eye may report chronic or intermittent redness or discharge and may interpret these symptoms as being related to an infectious cause.

●Patients whose eyes are irrigated after a chemical splash may have redness and discharge; this is often related to the mechanical irritation of irrigation rather than superinfection.

●A patient with an ocular foreign body that was spontaneously expelled may have redness and discharge for 12 to 24 hours.

EVALUATION AND DIAGNOSIS

Distinguishing between types of conjunctivitis — Key distinguishing features (including examination findings) between bacterial, viral and allergic conjunctivitis are also presented in the table and graphic (table 1 and figure 2). Patients may report discomfort which is highly subjective, varies among patients, and could be described as grittiness, burning, foreign body sensation, or pain. Typically, patients with conjunctivitis of any etiology can open the eye or eyes spontaneously, which is not the case for keratitis (see "The red eye: Evaluation and management"). There can be varying degrees of lid swelling and conjunctival chemosis that is not helpful in discerning etiology.

General approach — Conjunctivitis is a clinical diagnosis of exclusion, made on the basis of history and physical examination. Patients often call all cases of red eye "conjunctivitis" and presume that all cases are bacterial and require antibiotics. When a patient calls to report "conjunctivitis" or "pink eye," clinicians should not accept that as a diagnosis but should rather review the history, symptoms, and signs prior to treating. A detailed description of how to take a history and examine a patient with a red eye is discussed elsewhere. (See "The red eye: Evaluation and management".)

●History – Typical features of conjunctivitis include a history of morning crusting and daytime redness and discharge. A history of itching is highly suggestive of allergic conjunctivitis.

It is worthwhile to elicit the character of the ocular discharge, as patients may refer to all discharge as "pus." In bacterial conjunctivitis the complaint of discharge predominates, while in viral and allergic conjunctivitis patients report a burning and gritty feeling or itching (figure 2).

A recent history of trauma should prompt investigation for etiologies other than conjunctivitis.

A history of contact lens use should prompt specific evaluation for keratitis. (See 'Contact lens wearers' below.)

Warning signs for sight-threatening conditions should be excluded. (See 'Reasons for urgent ophthalmologic referral' below.)

Certain features on history raise concern for more serious diagnoses and should prompt ophthalmologic referral. These include photophobia, severe headache with nausea, and severe foreign body sensation. (See 'Reasons for urgent ophthalmologic referral' below.)

●Examination – On examination, the redness or injection in conjunctivitis should be diffuse, involving the bulbar (globe) conjunctiva for 360 degrees as well as the palpebral (tarsal) conjunctiva (the mucus membrane on the inner surface of the lids).

•If the conjunctival injection is localized rather than diffuse, another diagnosis such as foreign body, pterygium, or episcleritis should be considered. (See "Pterygium" and "Episcleritis".)

•If the tarsal conjunctiva is spared, suspicion should be raised for keratitis, iritis, and angle-closure glaucoma. These serious conditions cause a red eye with 360 degree involvement of the bulbar conjunctiva, often in a ciliary flush pattern, but without tarsal conjunctival involvement. (See 'Reasons for urgent ophthalmologic referral' below.)

The diagnosis of conjunctivitis can be made in a red eye if there is discharge, vision is normal (or unchanged), and there is no evidence of keratitis, iritis, or angle-closure glaucoma (see "The red eye: Evaluation and management"). In addition, on examination there should be no focal pathology in the lids such as hordeolum (stye), nodular ulceration or mass suspicious for neoplasia, or blepharitis (diffuse eyelid margin thickening and hyperemia with lash crusts) (picture 6). In these other disorders, conjunctival hyperemia, if present, is reactive rather than primary.

Certain features on examination raise concern for more serious diagnoses and should prompt ophthalmologic referral. (See 'Reasons for urgent ophthalmologic referral' below.)

Limited role for testing — Cultures or stains are not necessary for the initial diagnosis and therapy of conjunctivitis, and ophthalmologists typically do not generally perform cultures even when they are referred cases that have not responded to initial therapy. The exception is patients with signs and symptoms of hyperacute conjunctivitis in whom Giemsa and Gram stains may be helpful to identify N. gonorrhoeae. (See 'Hyperacute bacterial conjunctivitis' above.)

A rapid (10-minute) test for adenoviral conjunctivitis is available, however, lack of reimbursement limits its wide adoption. This test has reasonable sensitivity and specificity under study conditions [15] and might aid clinicians in determining a viral as opposed to bacterial etiology, thereby avoiding empiric antibiotic therapy. Elimination of empiric antibiotic therapy has theoretical benefits including prescription drug savings, avoidance of side effects, and reduction of antibiotic resistance, and a modelled cost-effectiveness analysis suggests a potential for significant cost savings with point of care (POC) testing [16].

Swabbing for culture, stains, and direct antibody or polymerase chain reaction (PCR) testing is typically reserved only for atypical or chronic cases that fail to improve or respond to therapy.

Contact lens wearers — The diagnosis of conjunctivitis should be made carefully in contact lens wearers, who are subject to myriad secondary chronic conjunctivitides that require a change in contact lens fit, lens type, or lens hygiene and may require suppression of hypersensitivity. Soft contact lens wearers have a high risk of pseudomonal keratitis, especially with use of extended-wear lenses [17,18]. This causes an acute red eye and discharge in association with an ulcerative keratitis. The ulcerative keratitis can lead to ocular perforation within 24 hours if it is not recognized and treated appropriately. Thus, the presence of keratitis should be ruled out prior to presuming and treating conjunctivitis. Keratitis causes objective foreign body sensation, and the patient is usually unable to spontaneously open the eye or keep it open; there is typically a corneal opacity visible with a penlight (picture 7). (See "The red eye: Evaluation and management" and "Complications of contact lenses".)

Reasons for urgent ophthalmologic referral — The following warning signs should prompt urgent referral to an ophthalmologist:

●Reduction of visual acuity (concerns about infectious keratitis, iritis, angle-closure glaucoma).

●Ciliary flush – A pattern of injection in which the redness is most pronounced in a ring at the limbus, (the transition zone between the cornea and the sclera). This is concerning for infectious keratitis, iritis, and angle-closure glaucoma.

●Photophobia (concerns about infectious keratitis, iritis).

●Severe foreign body sensation that prevents the patient from keeping the eye open (concerns about infectious keratitis).

●Corneal opacity (concerns about infectious keratitis).

●Fixed pupil (concerns about angle-closure glaucoma).

●Severe headache with nausea (concerns about angle-closure glaucoma).

●Suspicion for hyperacute bacterial conjunctivitis or epidemic keratoconjunctivitis (EKC). (See 'Hyperacute bacterial conjunctivitis' above and 'Epidemic keratoconjunctivitis' above.)

Note that photophobia and severe foreign body sensation are also characteristic of corneal abrasion, a condition that can be initially treated in the primary care or emergency care setting, with referral to ophthalmology if symptoms persist. Corneal abrasion is accompanied by tearing, but typically there is no discharge. (See "Corneal abrasions and corneal foreign bodies: Management" and "Corneal abrasions and corneal foreign bodies: Clinical manifestations and diagnosis".)

THERAPY

General considerations

Preventing contagion — Bacterial and viral conjunctivitis are both highly contagious and spread by direct contact with secretions or contact with contaminated objects. Infected individuals should not share handkerchiefs, tissues, towels, cosmetics, linens, or eating utensils.

Need for examination prior to therapy — Providers are often pressured to prescribe antibiotics for conjunctivitis, even when there is nothing to suggest a bacterial process. This can be a particular issue for parents or other caretakers because most daycare centers and schools require that students with conjunctivitis receive 24 hours of topical therapy before returning to school. Patients may sometimes request to be treated without being examined. (See 'Returning to work, school, or sports' below.)

We believe that no patient should be treated for conjunctivitis without an examination. In principle, only those diagnosed with bacterial conjunctivitis should receive antibiotics. If the decision is made to prescribe antibiotics without an examination, we use an inexpensive nontoxic antibiotic such as erythromycin ophthalmic ointment or trimethoprim-polymyxin B ophthalmic drops, except in the case of contact lens wearers (see 'Common conjunctivitis in contact lens wearers' below). Ointment is preferred over drops for children. Dosing for antibiotics is provided in the table (table 2).

There are emerging data on the value of online treatment of conjunctivitis. In a study comparing asynchronous online text-based e-visits (without photo or video), phone calls, and in-person encounters among pediatric patients with conjunctivitis, antibiotic prescribing was greater with phone call encounters (41.6 percent) than with e-visits (25.7 percent) or face-to-face encounters (19.8 percent) [19].

No role for corticosteroid use — Ophthalmic corticosteroids (either alone or in combination steroid/antibiotic drops) have no role in the management of acute conjunctivitis by primary care clinicians [20]. Corticosteroids can cause sight-threatening complications (eg, corneal scarring, melting, and perforation) when used inappropriately. Chronic ophthalmic corticosteroid treatments can also cause cataract and glaucoma [21,22].

Ophthalmologists may prescribe topical corticosteroids in certain cases of ocular allergy, viral keratitis, and chronic blepharitis. Use in these conditions should be supervised by an ophthalmologist as discussed in separate topic reviews. (See "Allergic conjunctivitis: Management", section on 'Corticosteroids' and "Atopic keratoconjunctivitis", section on 'Topical corticosteroids' and "Vernal keratoconjunctivitis", section on 'Topical corticosteroids' and "Blepharitis", section on 'Topical glucocorticoids'.)

Specific therapy — Therapy should be directed at the likely etiology of conjunctivitis suggested by the history and physical examination (table 1).

Bacterial

Common conjunctivitis — Bacterial conjunctivitis is self-limited in most cases, although topical antibiotics may shorten the clinical course if given before day 6 [4,23,24]. In most cases, the choice of whether to use antibiotics for the treatment of acute bacterial conjunctivitis is driven by values and preferences (for example, in back to work or school situations). However, antibiotic treatment is required for acute conjunctivitis in contact lens wearers as well as for cases of adult inclusion conjunctivitis or hyperacute bacterial conjunctivitis. (See 'Common conjunctivitis in contact lens wearers' below and 'Adult inclusion conjunctivitis treatment' below and 'Hyperacute bacterial conjunctivitis treatment' below.)

Treatment options for acute bacterial conjunctivitis are presented in the table (table 2). Preferred choices for noncontact lens wearers include erythromycin ophthalmic ointment or trimethoprim-polymyxin B drops. The dosing is 0.5 inch (1.25 cm) of erythromycin ointment deposited inside the lower lid, or one to two drops of trimethoprim-polymyxin B, four times daily for five to seven days to the affected eye. These agents are preferred as they are inexpensive, widely available, and non-toxic, and they have low rates of hypersensitivity. Common alternative therapies include bacitracin ointment (limited by cost) and bacitracin-polymyxin B ointment (limited by cost and patient sensitivity).

Ointment is preferred over drops for children, those with poor compliance, or those in whom it is difficult to administer eye medications. Ointment stays on the lids and can have therapeutic effect even if it is not clear that any of the dose was applied directly to the conjunctiva. Because ointments blur vision for 20 minutes after the dose is administered, drops are preferable for most adults who need to read, drive, and perform other tasks that require clear vision immediately after dosing.

Patients should respond to treatment within one to two days by showing a decrease in discharge, redness, and irritation. At this point it is reasonable to reduce the dose from four times daily to twice daily. Patients who do not respond should be referred to an ophthalmologist.

Some alternative treatment options have specific limitations:

●Azithromycin is approved in the United States as an ophthalmic solution for bacterial conjunctivitis in patients one year of age and older. It is dosed less frequently than other ophthalmic solutions (one drop twice daily for two days, then one drop daily for five days) but is considerably more expensive than erythromycin or sulfacetamide, and its availability raises a concern about promoting the emergence of organisms resistant to azithromycin, which could limit its use for other infections [25].

●Sulfacetamide ophthalmic drops are also available but are not a first-line option because of the potential for rare but serious allergic events.

●Aminoglycoside drops and ointments are poor choices since they are toxic to the corneal epithelium and can cause a reactive keratoconjunctivitis after several days of use.

●Chloramphenicol drops are a generally inexpensive and well-tolerated option used widely around the world for the treatment of bacterial conjunctivitis. However, topical use of chloramphenicol has been associated with the very rare but catastrophic complications of bone marrow hypoplasia, aplastic anemia, and death and is not marketed or used in the United States for the treatment of ocular infections [26].

●Fluoroquinolones are not first-line therapy for routine cases of bacterial conjunctivitis because of concerns regarding emerging resistance and cost. The exception is conjunctivitis in a contact lens wearer due to the high incidence of Pseudomonas infection.

Common conjunctivitis in contact lens wearers — For all contact lens wearers with bacterial conjunctivitis, we suggest antibiotic treatment due to the increased risk of keratitis and/or infection with gram-negative organisms. Fluoroquinolones are the preferred agent to treat bacterial conjunctivitis in contact lens wearers due to the high incidence of Pseudomonas infection. Patients should stop wearing contact lenses. If there is any corneal opacity or suspicion of keratitis, the patient should be evaluated by an ophthalmologist. Microbial keratitis is more likely if there is foreign body sensation or reduced vision (see "Complications of contact lenses", section on 'Infectious keratitis') Chronic conjunctivitis in a contact lens wearer is best addressed by a knowledgeable optometrist or ophthalmologist.

If the diagnosis is bacterial conjunctivitis, contact lens wear can resume when the eye is white and has no discharge for 24 hours after the completion of antibiotic therapy, or, in the case of viral conjunctivitis, when the eye is white with no discharge. The lens case should be discarded and the lenses subjected to overnight disinfection or replaced if disposable.

Adult inclusion conjunctivitis treatment — Antibiotic treatment for adult inclusion conjunctivitis requires systemic therapy (typically with doxycycline, tetracycline, erythromycin, or azithromycin) to eradicate the C. trachomatis infection. (See "Trachoma", section on 'Treatment'.)

Hyperacute bacterial conjunctivitis treatment — Hyperacute bacterial conjunctivitis due to Neisseria typically requires systemic therapy and is discussed elsewhere. (See "Treatment of uncomplicated gonorrhea (Neisseria gonorrhoeae infection) in adults and adolescents", section on 'Conjunctivitis'.)

Viral — There is no specific topical or systemic antiviral agents for the treatment of viral conjunctivitis. Systemic antibiotic and antiviral therapies play no role.

Symptomatic relief may be achieved with:

●Topical antihistamine/decongestants, which are available over the counter (naphazoline-pheniramine, ketotifen, olopatadine and others). Some patients find relief in switching from one to another, although there is little evidence that one is superior for symptoms.

●Warm or cool compresses.

●Nonantibiotic lubricating agents such as those used for noninfectious conjunctivitis. There are a wide variety of products on the market with various formulations, none proven superior for symptomatic relief (table 2). (See 'Noninfectious, noninflammatory conjunctivitis' above.)

Patients must be told that the eye irritation and discharge may get worse for three to five days before getting better, that symptoms can persist for two to three weeks, and that use of any topical agent (antibiotics or antihistamine/decongestant) for that duration might result in irritation and toxicity, which can itself cause redness and discharge. Clinicians must be wary of trying one agent after another in patients with viral conjunctivitis who are expecting drugs to "cure" their symptoms. Patient education is often more effective than prolonged or additional therapies for patients who experience improvement but incomplete resolution of symptoms after a few days.

Allergic — There are numerous therapy options available for allergic conjunctivitis, including naphazoline-pheniramine, ketotifen, olopatadine, and others (table 2 and table 3) [27,28]. This is discussed elsewhere (see "Allergic conjunctivitis: Management"). Ketorolac drops should not be used for viral or allergic conjunctivitis. Although these are labelled for relief of itching due to seasonal allergic conjunctivitis, ketorolac is a nonsteroidal antiinflammatory drug (NSAID), and post-market experience reveals that topical NSAIDs are associated with corneal adverse effect in some susceptible patients, which may become sight-threatening. (See "Allergic conjunctivitis: Clinical manifestations and diagnosis".)

Toxic — The primary approach to toxic conjunctivitis is recognition and removal of the offending agent. Stopping as many topical agents as feasible is a good first step. However, glaucoma drops should not be stopped except by the prescribing clinician, as pressure rise may cause irreversible vision loss. Recovery may take weeks rather than days. With some agents, there is paradoxical rebound redness when agents are stopped, making adherence to medical advice difficult for patients. Patients in whom a glaucoma medication is thought to be the culprit, or those with severe symptoms or problematic rebound redness, should be referred to an ophthalmologist for management. (See "Toxic conjunctivitis".)

Noninfectious noninflammatory — The conjunctival surface regenerates rapidly from insults that precipitate noninfectious conjunctivitis, leading to spontaneous resolution of symptoms. Nevertheless, these patients may have symptom relief with the use of topical lubricants, which can be purchased over the counter as drops and ointments (table 2). Preservative-free preparations are more expensive and are necessary only in severe cases of dry eye or in highly allergic patients when frequency of use greater than six times daily is required.

Lubricant drops can be used as often as hourly for one to two days with no side effects. The ointment provides longer-lasting relief but blurs vision; thus, many patients use the ointment only at bedtime. It may be worthwhile to switch brands if a patient finds one brand of drop or ointment irritating since each preparation contains different active ingredients, vehicles, and preservatives.

Persistent symptoms — Patients with acute bacterial conjunctivitis usually respond to treatment within one to two days by showing a decrease in discharge, redness, and irritation. Patients who do not respond should be referred to an ophthalmologist. Patients with other forms of acute conjunctivitis (eg, viral or allergic) usually improve within two weeks, and those who do not should also be referred to an ophthalmologist.

Diagnoses to consider in patients with persistent symptoms include dry eye (see "Dry eye disease"), medicamentosa (drug toxicity) (see "Toxic conjunctivitis"), pterygium (see "Pterygium"), blepharoconjunctivitis (see "Blepharitis"), and adult inclusion conjunctivitis. (See 'Chronic chlamydial infections' above.)

RETURNING TO WORK, SCHOOL, OR SPORTS

●Work/school – Clinicians are often asked to advise patients and families or caregivers as to when it is safe to return to work or school. Bacterial and viral conjunctivitis are both highly contagious and spread by direct contact with secretions or contact with contaminated objects. Infected individuals should not share handkerchiefs, tissues, towels, cosmetics, linens, or eating utensils. The safest approach to prevent spread to others is to stay home until there is no longer any discharge, but this is not feasible for most students and for those who work outside the home. Most daycare centers and schools require that students receive 24 hours of topical therapy before returning to school. Such therapy will probably reduce the transmission of conjunctivitis due to bacterial infection but will do nothing to reduce the spread of viral infections.

We suggest advising patients to consider that their problem is like a cold, and their decision to return to work or school should be similar to the one they would make in that situation. Those who have contact with the very old, the very young, and immune-compromised individuals should take care to avoid spread of infection from their eye secretions to these susceptible people.

●Sports – For bacterial conjunctivitis, patients should not return to playing sports until they have used an antibiotic for a minimum of 24 hours and had resolution of eye drainage. Clearance to return to play for viral conjunctivitis depends on the sport. Athletes who participate in sports that are individual and/or noncontact and which do not involve shared equipment (eg, cross-country running) can return when they feel able and can see clearly. If these athletes return before symptoms have resolved, they should be advised not to touch their eyes and to wash their hands frequently. Athletes who participate in contact sports, sports with shared equipment (eg, gymnastics), or water-based sports may return to play once daytime discharge has abated, typically after about five days.

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Conjunctivitis (pink eye) (The Basics)")

●Beyond the Basics topics (see "Patient education: Conjunctivitis (pink eye) (Beyond the Basics)" and "Patient education: Allergic conjunctivitis (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Causes – Conjunctivitis may be infectious (bacterial or viral) or noninfectious (allergic, toxic, dryness, and others). Most infectious conjunctivitis is probably viral; bacterial conjunctivitis is more common in children than in adults. (See 'Classification and epidemiology' above.)

●Diagnosis – The diagnosis of conjunctivitis is made in a patient with a red eye and discharge only if the vision is normal (or unchanged) and there is no evidence of keratitis, iritis, or angle-closure glaucoma. Warning signs for alternative conditions that should prompt evaluation by an ophthalmologist are discussed above. (See 'Reasons for urgent ophthalmologic referral' above and 'Evaluation and diagnosis' above.)

●Distinguishing between types – Distinguishing between bacterial, viral and allergic conjunctivitis can be achieved on the basis of history and physical examination. All etiologies can cause symptoms of the eyes being stuck closed in the morning. Helpful distinguishing characteristics are presented in the table and graphic (table 1 and figure 2). (See 'Causes and clinical manifestations' above.)

•Bacterial – Bacterial conjunctivitis should only be diagnosed in patients with thick purulent discharge that continues throughout the day and should be confirmed by a clinician examination. The discharge can generally be seen at the lid margins and at the corner of the eye (picture 1). Bacterial conjunctivitis is usually unilateral but can be bilateral. (See 'Bacterial conjunctivitis' above.)

Hyperacute bacterial conjunctivitis may be due to Neisseria infection; this can be severe and sight-threatening. Such patients require urgent ophthalmology referral (picture 2). (See 'Hyperacute bacterial conjunctivitis' above.)

•Viral – Viral conjunctivitis typically presents as injection, mucoid or serous discharge, and a burning or gritty feeling in one eye. It may be an isolated manifestation or part of a systemic viral illness. The second eye usually becomes involved within 24 to 48 hours; unilateral viral infection may occur. Usually there is profuse tearing rather than discharge; the latter may be present on close examination. The symptoms generally worsen for three to five days and resolve over one to two weeks. (See 'Viral conjunctivitis' above.)

•Allergic – Allergic conjunctivitis typically presents as bilateral redness, watery discharge, and itching. Itching is the cardinal symptom of allergy, distinguishing it from a viral etiology. Patients with allergic conjunctivitis often have a history of atopy, seasonal allergy, or specific allergy. (See 'Allergic conjunctivitis' above.)

●Treatment of bacterial conjunctivitis - The use of antibiotics for bacterial conjunctivitis is individualized. Most patients do not require antibiotics:

•Noncontact lens wearers - most cases are self-limited and do not require antibiotics. However, topical antibiotics may shorten the clinical course and allow for quicker return to work or school. For noncontact lens wearers who select antibiotic treatment, we suggest either erythromycin ophthalmic ointment or trimethoprim-polymyxin drops over alternative agents (table 2) (Grade 2C). Either agent is administered four times daily for five to seven days. Ointment may be preferred in those with difficulty administering eye drops (eg, children) but may blur the vision. (See 'Bacterial' above.)

•Limited role for antibiotics – For the following patients with bacterial conjunctivitis, antibiotic treatment is warranted:

-Contact lens wearers – For all contact lens wearers with bacterial conjunctivitis, we suggest antibiotic treatment. (Grade 2C) A topical fluoroquinolone is preferred due to the high incidence of Pseudomonas infection. Patients should discontinue contact lens use until there is no discharge for 24 hours after completion of therapy; used lenses and lens case should be discarded. If there is any corneal opacity or suspicion of keratitis, the patient should be evaluated by an ophthalmologist. (See 'Common conjunctivitis in contact lens wearers' above.)

-Hyperacute bacterial conjunctivitis due to Neisseria – This requires systemic therapy and management by an ophthalmologist. (See "Treatment of uncomplicated gonorrhea (Neisseria gonorrhoeae infection) in adults and adolescents", section on 'Conjunctivitis'.)​

-Chlamydial infection (typically a chronic infection) – This requires systemic antibiotic therapy and management by an ophthalmologist. (See "Trachoma", section on 'Treatment'.)

•Referral for persistent symptoms – Patients with presumed bacterial conjunctivitis who do not respond to topical antibiotic treatment within a few days should be referred to an ophthalmologist. (See 'Persistent symptoms' above.)

●Treatment of viral, allergic, or noninfectious conjunctivitis

•Viral - Topical antihistamine/decongestants and/or lubricating agents may provide symptom relief (table 2). Contact lens wearers should temporarily discontinue lens use and may resume when symptoms resolve. Used lenses and lens case should be discarded. (See 'Viral' above.)

•Allergic - Minimize exposure to the allergen. Use of topical lubricants, cool compresses, and topical or systemic antihistamines may provide symptom relief (table 3) (See "Allergic conjunctivitis: Management".)

•Noninfectious – For patients with noninfectious conjunctivitis, topical lubricants may provide symptom relief and can be used as often as six times daily (table 2). (See 'Noninfectious noninflammatory' above.)

●Treatments to avoid – Avoid topical corticosteroids and topical NSAIDS – Ophthalmic corticosteroids (alone or in combination preparations) should not be prescribed by primary care clinicians for acute conjunctivitis; they can cause sight-threatening complications when used inappropriately. Ketorolac should not be used to treat allergic conjunctivitis. Topical NSAIDS (nonsteroidal anti-inflammatory drugs) are associated with corneal adverse effect in susceptible patients. (See 'No role for corticosteroid use' above and 'Allergic' above.)

●Infection control – Infection control and return to work or school – Bacterial and viral conjunctivitis are highly contagious. Advise patients to limit spread by avoiding direct contact with secretions or contaminated objects (eg, makeup, contact lenses). (See 'Preventing contagion' above and 'Returning to work, school, or sports' above.)

•For bacterial conjunctivitis, postpone return to school or work until 24 hours of treatment and resolution of discharge.

•Patients with viral conjunctivitis may remain infectious for a variable period related to the underlying viral syndrome; return to activities is individualized.