Conjunctivitis is an inflammation of the conjunctiva resulting in dilatation of the conjunctival blood vessels, causing the eye to appear red. Inflammation may be limited to the conjunctiva (primary conjunctivitis) or may occur secondary to diseases affecting other parts of the eye, e.g. iritis. There are a number of causes of conjunctivitis outlined in the separate article Conjunctivitis where more detail is provided about:

• Viral conjunctivitis.
• Other less common types of conjunctivitis.

We also have separate articles for Allergic Conjunctivitis and Ophthalmia Neonatorum.

If you think that this is a conjunctival problem that is not conjunctivitis, see separate article Conjunctival Problems where you will find out more about assessing the conjunctiva, together with details on:

• Conjunctival trauma.
• Degenerative conditions of the conjunctiva (pinguecula, pterygium, concretions, retention cysts).
• Other inflammatory conditions (mucus fishing syndrome, ligneous conjunctivitis).
• Blistering mucocutaneous diseases (cicatricial pemphigoid, Stevens-Johnson syndrome).
• Conjunctival lesions (pigmented, squamous tumours and other tumours).

Background

Bacterial conjunctivitis is usually a benign self-limiting illness,¹ although it can sometimes be serious or signify a severe underlying systemic disease. Occasionally, significant ocular and systemic morbidity may result.²

Epidemiology

• This is one of the most common ocular problems seen in the community.³
• In adults, bacterial conjunctivitis is less common than viral conjunctivitis; although estimates vary widely, it is thought to account for no more than half of all cases of acute infective conjunctivitis.⁴
• It is most commonly caused by Staphylococcus spp., Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.⁵
• In children, bacterial conjunctivitis is more common than viral and is mainly caused by H. influenzae, S. pneumoniae and M. catarrhalis.

Presentation

History

Relevant aspects of the history include:

• Nature of the problem:
  • Discomfort - burning or gritty but not sharp.
  • Pain - should be minimal; significant pain suggests a more serious diagnosis.
  • Vision - usually normal, although 'smearing', particularly on waking, is common.
  • Discharge - this tends to be thick rather than watery.
  • Associated symptoms such as photophobia which should be absent or, at most, mild. Significant photophobia suggests severe adenoviral conjunctivitis or some degree of corneal involvement.
• Contact lens wear: could this be (or lead to) a problem of the (vulnerable) cornea?
• Time course: onset, duration - where this is chronic, you may have to consider venereal disease in people at a sexually active age.
• Use of over-the-counter medication: could this be a reaction to previously administered drops or ointment?
• Social aspect - has anybody else had it (family, school, work?) and are there issues about staying at home during the course of the illness?

Findings

• 'Red eye' with uniform engorgement of all the conjunctival blood vessels.
• Bacterial conjunctivitis may often be distinguished from other types of conjunctivitis by the presence of a yellow-white mucopurulent discharge. Eyes may be difficult to open in the morning, glued together by discharge.
• There is also usually a papillary reaction (small bumps on the palpebral conjunctiva, appearing like a fine velvety surface). The presence of follicles is more likely to indicate viral conjunctivitis.
• Bacterial conjunctivitis is usually bilateral (but often sequential).³
• Check visual acuity - this should be normal, other than the mild and temporary blur secondary to the discharge which can be blinked or wiped away.

Is this bacterial?

It is not always easy to determine whether the patient's simple, acute conjunctivitis is bacterial or not but this is important as it may determine the subsequent management plan. Ultimately, swabbing the eye provides the most accurate diagnostic answer but it is clearly not practical to do this for every patient. A study has shown that, in adult patients, there is a significant chance that the infection is bacterial when there is a combination of:⁴

• A positive previous history of infectious conjunctivitis.
• An itch present.
• A mucopurulent discharge ('glue eye').

However, in severe, resistant, atypical cases or in immunosuppressed patients, swabbing for culture and sensitivities is important.³
When patients describe their eyes glued together in the morning, this doesn't necessarily mean that there is a purulent discharge. Viral and allergic conjunctivitis often result in lids that are matted shut in the morning with mucopurulent material. However, these patients actually have crusting of the lashes due to drying of tears and serous secretions, not the wet, sticky, mucopurulent matting characteristic of bacterial conjunctivitis.

Differential diagnosis

Unilateral conjunctivitis for more than a few days is unusual and should prompt a thorough assessment for the possibility of other, often more serious, eye conditions.

Common problems

• Viral conjunctivitis: a watery discharge is commonly seen with viral conjunctivitis.
• Allergic conjunctivitis: suggested by moderate-to-severe itching, rhinitis or other hay fever symptoms and/or cobblestone elevations on the tarsal conjunctiva.
• A foreign body may mimic conjunctivitis: everting the upper eyelid for examination, and staining with fluorescein is recommended if a foreign body is suspected.
• Eye trauma: this may not always be remembered by the patient and can be mechanical or chemical.
• Episcleritis: mild, acute-onset localised redness in one or both eyes.
• Nasolacrimal blockage - this is very common in neonates and results in a sticky, discharging eye. The key thing is that the eye is not red and that the baby is otherwise well.
• Blepharoconjunctivitis and meibomianitis: particularly seen in people with acne rosacea.
• Dry eye syndrome.

Serious problems

• Acute glaucoma - look out for a reduced visual acuity, hazy cornea, fixed pupil and acute systemic malaise.
• Uveitis - marked pain, photophobia and possibly decreased visual acuity should ring alarm bells in a 'conjunctivitis' not responding to conventional treatment, particularly in patients with previous episodes (they usually recognise their symptoms) or with systemic illnesses predisposing to uveitis.
• Keratitis: often presents with a unilateral, acutely painful, photophobic, intensely injected eye. Acanthamoeba keratitis: may be seen in soft contact lens wearers with poor hygiene, prolonged wear, or swimming while wearing lenses.
• Scleritis: usually presents with severe, boring ocular pain.
• Orbital cellulitis: should be suspected if the person is unwell with red eye, blurred vision, headache, diplopia, eyelid oedema and erythema, restricted ocular motility and pain on movement. The sinuses are often but not always involved. Requires urgent admission.
• Ocular herpes simplex: typically presents as a painful, red eye with dendritic ulcer seen on staining with fluorescein.
• Herpes zoster ophthalmicus: is there any telltale rash (or severe herpetic pain which can occur before the rash)? This may be associated with conjunctivitis.
• Hyperacute conjunctivitis: severe sight-threatening ocular infection that warrants immediate ophthalmic work-up and management. The infection is characterised by a copious yellow-green purulent discharge that re-accumulates after being wiped away. The most common pathogens are Neisseria gonorrhoeae and N. meningitidis.

Different types of bacterial conjunctivitis

Simple bacterial conjunctivitis

• Essence - bacterial infection may be by commensals or exogenous bacteria. The common culprits include S. aureus, S. epidermidis, S. pneumoniae and, in children, H. influenzae. Bacterial conjunctivitis accounts for no more than 50% of cases of infective conjunctivitis and is more common in children than in adults.
• Risk factors⁶ - infants and children: nasolacrimal duct obstruction, concomitant otitis media or pharyngitis, exposure to an affected individual. Adults: as above, lid malpositions, severe tear deficiency, immunosuppression and trauma.
• Suggestive symptoms - unilateral, uncomfortable (gritty or burning) red eye with a yellow-white mucopurulent discharge. Lids are often stuck shut on waking. There may be mild photophobia.
• Signs to look for - crusted lids (± oedema), evidence of mucous strands/discharge, velvety appearance of conjunctiva with presence of papillae and, occasionally, superficial punctate keratitis.
• Management - discontinue contact lens wear, swab if there is a large quantity of discharge, advise careful two to three times daily lid hygiene. In adults, simple bacterial conjunctivitis is usually a self-limiting condition lasting 10-14 days:⁷ good lid hygiene is enough. However, if the decision is made to use antibiotics (see 'Treatment with antibiotics', below), chloramphenicol (drug of choice) or fusidic acid are suitable choices. Fluoroquinolones are reserved for more serious infections that need to be seen in a specialist unit.
• Additional notes - invite the patient to return if there is no improvement over a week or so, as these infections can be associated with complications such as otitis media (25% of children with H. influenzae conjunctivitis)⁸ and corneal involvement (particularly in contact lens wearers).

Gonococcal conjunctivitis

• Essence - an infection of hyperacute onset (12-24 hours) caused by the same N. gonorrhoeae responsible for venereal genitourinary tract infections. This organism is able to invade intact corneal epithelium (so non-contact lens wearers are no less at risk).⁷
• Risk factors - contact with infected individuals, presence of other sexually transmitted diseases.
• Suggestive symptoms - rapid onset of unilateral/bilateral hyperpurulent red eye.
• Signs to look for^7,9 - tender lid oedema, profuse discharge, keratitis (look for oedema, fluorescein uptake, decreased visual acuity and photophobia), preauricular lymphadenopathy.
• Management - discontinue contact lens wear, swab, refer on for further assessment. After swabbing, systemic treatment will be with cefotaxime (length depends on whether there is corneal involvement or not) ± topical antibiotics.
• Additional notes - the patient should be assessed for evidence of other venereal disease and treated concurrently for chlamydial infection. They should be informed of the nature of this infection and sexual partners should also be traced and treated as appropriate.⁶

Chlamydial infection

• Essence⁷ - chlamydial inclusion conjunctivitis is caused by serotypes D to K of Chlamydia trachomatis. It is transmitted by autoinoculation or eye-to-eye spread. It is a sexually transmitted disease with an incubation period of 1 week and may be associated with urethritis or cervicitis.
• Risk factors - contact with infected individuals, presence of other sexually transmitted diseases.
• Suggestive symptoms - chronic low-grade conjunctivitis (may persist for 3 to 12 months if left untreated) with a green stringy discharge in the morning.
• Signs to look for - inferior conjunctival follicles, superior corneal pannus (superficial corneal neovascular area), palpable preauricular lymph nodes.
• Management - discontinue contact lens wear, topical treatment with tetracycline ointment (qds for 6 weeks) and systemic doxycycline (100 mg bd for 1-2 weeks) or azithromycin (1 g single dose) or erythromycin (500 mg qds for 1 week if tetracycline is contra-indicated). There is ongoing debate as to which antibiotic is most effective (alone or in combination) but doxycycline is a good starting drug if there are no contra-indications and, in small studies, it has been associated with 100% cure rate.¹⁰
• Additional notes - trachoma is caused by serotypes A to C of C. trachomatis and arises in the context of poor sanitation. It is the third most common cause of blindness worldwide, causing severe conjunctival cicatricial changes and secondary corneal ulceration and scarring.

Ophthalmia neonatorum

See separate related Ophthalmia Neonatorum article.

• Essence - this is conjunctivitis within the first 28 days of life. It may be chemically induced or arise as a result of infection. A number of pathogens can be involved through either contamination from the maternal genital tract (N. gonorrhoeae, C. trachomatis, group B beta haemolytic streptococcus) or by cross infection (S. aureus, coliforms, pseudomonas). Chlamydial infection (which presents 5-19 days after birth) is the most common cause of neonatal conjunctivitis⁷ and is a notifiable disease. It may be associated with systemic chlamydial infection, otitis, rhinitis and pneumonia. Gonococcal infection presents 1-7 days after birth.⁶
• Risk factors - vaginal delivery by infected mother.
• Signs to look for - purulent/mucoid discharge from one or both eyes, associated with diffuse conjunctival injection. There may be eyelid oedema.
• Management^6,9 - refer to ophthalmologists and look into treating maternal infection (± sexual partners). These babies will receive systemic treatment (erythromycin for chlamydial infection and ceftriaxone for gonococcal infection) and will be monitored extremely closely; they are likely to be admitted for gonococcal infection in order to monitor for development of disseminated infection.

Management issues

General points

• Advise the patient to discontinue contact lens wear until 24-48 hours after resolution of symptoms.
• Although current guidelines do not recommend staying away from school or work, common sense should prevail and it seems reasonable for those who are more likely to transmit the infection (e.g. young children) to stay at home until the symptoms have subsided. Some establishments have specific rules about this.
• Remind the patient of other precautions to reduce transmission of infection, e.g. no towel or make-up sharing, and avoid rubbing the eyes.
• Advise the patient to return if symptoms worsen within the week or persist beyond 10 days - it may be necessary to rethink the diagnosis.
• All infants with infective conjunctivitis within the first 28 days of life should be referred to a specialist.⁵

Treatment with antibiotics

It is clear that antibiotics are overprescribed for infective conjunctivitis - £4.7million is spent on the NHS to treat 80% of cases of infective conjunctivitis when it is estimated that in no more than 50% of patients (probably much fewer) have bacterial infection.¹ The arguments for and against the use of topical antibiotics can be summarised as follows:

You may encounter some resistance to careful, conservative management. It is worth outlining the above points and a management decision can be made based on these. One option is to consider a 'watch and wait' approach for 7 days and start then if there is no improvement of symptoms.⁵ This has been shown to reduce medicalisation of the patient and antibiotic use overall.¹ If treatment is initiated, it should be continued until 48 hours after the redness has resolved.

Drops versus ointment

Generally, drops should be prescribed in preference to ointments when a patient is taking other eye drops. Ointments are messy and may smear, causing blurred vision that would be impractical for daytime use in many people. However, ointment maintains the concentration of antibacterial agent in the eye longer than drops and some people, such as the elderly with arthritic hands, find ointment easier to apply. Using drops by day and ointment by night is the ideal.

For more general information about ocular prescriptions, see separate article Eye Drugs - Prescribing and Administering.

Drugs used⁵

• Chloramphenicol has a broad spectrum of activity and is the drug of choice for superficial eye infections.⁵ It is bacteriostatic, with a relatively broad spectrum of action against most Gram-positive and Gram-negative bacteria. It is best avoided in people who have experienced myelosuppression during previous exposure to chloramphenicol, in those who have a blood dyscrasia or who have a family history of blood dyscrasias and in patients who are concurrently with other myelotoxic drugs. Avoid, in pregnant or breast-feeding women, as its safety has not been established.
  It should be avoided for prolonged periods, since it may increase the likelihood of sensitisation and resistance.
• Fusidic acid is useful for staphylococcal infections and is an alternative antibacterial agent to chloramphenicol. Several comparative trials have shown that topical fusidic acid is equally effective as topical chloramphenicol.¹² Consider this particularly in pregnant women, those with a personal or family history of blood dyscrasias, such as aplastic anaemia, and patients who are intolerant of chloramphenicol.
• Aminoglycosides have an incomplete coverage of Streptococcus spp. and Staphylococcus spp. and so this rules them out as first-line therapy. A relatively higher incidence of toxicity to the corneal epithelium has been recorded with prolonged use of aminoglycosides.
• Fluoroquinolones such as ciprofloxacin and ofloxacin should be reserved for serious ocular infections to limit the development of bacterial resistance. The fluoroquinolones have poor coverage of Streptococcus spp. Ciprofloxacin eye drops are licensed for corneal ulcers; intensive application (especially in the first 2 days) is required throughout the day and night.
• Gentamicin, ciprofloxacin, levofloxacin, ofloxacin, and polymyxin B are effective for infections caused by Pseudomonas aeruginosa (contact lens wearers are the particular risk group for pseudomonal infection).
• Trachoma (due to chronic infection with C. trachomatis) can be treated with oral azithromycin.

Complications

• Serious complications are rare in simple adult bacterial conjunctivitis.
• Corneal ulceration: healthy intact corneas are relatively resistant to infection. However, contact lens wearers may have compromised corneas due to hypoxia, foreign body tracts from debris trapped between lens and eye or staining from lens use. Damaged corneal epithelium provides a potential point of entry for micro-organisms.
• Chronic bacterial conjunctivitis can occur with eyelid disease such as blepharitis and meibomian gland inflammation.¹³
• Some organisms cause corneal or systemic complications, or both. Otitis media may develop in 25% of children with H. influenzae conjunctivitis,⁸ and systemic meningitis may complicate primary meningococcal conjunctivitis in 18% of cases.¹⁴ Pneumonia occurs in 10-20% of infants following chlamydial conjunctivitis and neonatal conjunctivitis can result in a severe localised infection of the eye and potentially serious systemic complications.⁵

Prognosis⁵

• Conjunctivitis is usually a self-limiting disease that does not cause any serious harm and spontaneous remission should occur within 7 days of onset.
• Chlamydial conjunctivitis in adults is a chronic condition lasting months.
• A recent meta-analysis has shown clinical remission by days 2-5 in 64% of people receiving placebo.¹¹

Document references

1. Everitt HA, Little PS, Smith PW; A randomised controlled trial of management strategies for acute infective conjunctivitis in general practice. BMJ. 2006 Aug 12;333(7563):321. Epub 2006 Jul 17. [abstract]
2. Marlin DS; Conjunctivitis, Bacterial, eMedicine, Jun 2009
3. Denniston AKO, Murray PI. Oxford Handbook of Ophthalmology, OUP (2008)
4. Rietveld RP, ter Riet G, Bindels PJ, et al; Predicting bacterial cause in infectious conjunctivitis: cohort study on informativeness of combinations of signs and symptoms. BMJ. 2004 Jul 24;329(7459):206-10. Epub 2004 Jun 16. [abstract]
5. Conjunctivitis - infective, Clinical Knowledge Summaries (2007)
6. Preferred practice pattern: conjunctivitis, American Academy of Ophthalmology, Sept 2008
7. Kanski J. Clinical Ophthalmology, A Systematic Approach, 5th Ed, Butterworth Heinemann (2003)
8. Wald ER; Conjunctivitis in infants and children. Pediatr Infect Dis 1997;J16(2suppl):S17-20 .
9. Kunimoto DY, Kanitkar KD, Makar MS; The Wills Eye Manual, 4th Edition, Lippincott, Williams and Wilkins (2004)
10. Low N; Chlamydia (uncomplicated, genital) BMJ Clin Evidence (online), last updated May 2006; Subscription required for full access to text
11. Sheikh A, Hurwitz B.; Antibiotics versus placebo for acute bacterial conjunctivitis. Cochrane Database of Systematic Reviews 2006, Issue 2. Art. No.: CD001211.
12. Horven I; Acute conjunctivitis. A comparison of fusidic acid viscous eye drops and chloramphenicol. Acta Ophthalmol (Copenh). 1993 Apr;71(2):165-8. [abstract]
13. Morrow GL, Abbott RL; Conjunctivitis. American Family Physician Vol. 57/No. 4. February 15, 1998
14. Barquet N, Gasser I, Domingo P, et al; Primary meningococcal conjunctivitis: report of 21 patients and review. Rev Infect Dis. 1990 Sep-Oct;12(5):838-47. [abstract]

Acknowledgements