Infective Conjunctivitis
Conjunctivitis is an inflammation of the conjunctiva, the thin mucous membrane lining the anterior part of the sclera (bulbar conjunctiva) and the undersurface of the eyelids (palpebral conjunctiva). It can be due to allergic or immunological reactions, infection, mechanical irritation, neoplasia, or contact with toxic substances.
This updated UKMLA guide to infective conjunctivitis is based on NICE CKS, which covers causes, risk factors, symptoms, viral conjunctivitis vs bacterial conjunctivitis, diagnosis, and management.
Causes
Up to 80% cases are viral conjunctivitis
- Most common due to adenovirus (65-90% of cases)
- Other: Herpes simplex, Varicella zoster, Molluscum contagiosum, Epstein-Barr, coxsackie and enteroviruses
Bacterial conjunctivitis
- Most common: Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae
- STIs (e.g. Chlamydia trachomatis, Neisseria gonorrhoea)
Contact lens users have a higher risk of gram -ve organism involvement (most commonly Pseudomonas aureginosa) [Ref]
Risk Factors
Risk factors include: [Ref]
- Close contact with an infected person
- Recent URTI (esp. for viral conjunctivitis)
- Children / nursery or school exposure (bacterial conjunctivitis is common in children)
- Poor hand hygiene / sharing towels or eye cosmetics
- Contact lens use
Clinical Features
General clinical features of conjunctivitis:
- Acute onset of conjunctival erythema
- Eye discomfort, often described as ‘grittiness’, ‘foreign body’, or ‘burning’ sensation
- Watering and discharge which may cause transient blurring of vision
Infective conjunctivitis often starts unilaterally, but may then spread to the other eye
It is difficult to differentiate viral and bacterial conjunctivitis clinically (but exam questions tend to follow the following stereotypical presentations):
| Feature | Viral conjunctivitis | Bacterial conjunctivitis |
|---|---|---|
| Discharge | Watery discharge | Purulent / mucopurulent discharge |
| Eyelids | Mild crusting | Crusting
Eyelids may be stuck together, especially on waking |
| Other features |
|
|
Features suggestive of specific causes:
| Cause | Description |
|---|---|
| Herpes simplex conjunctivitis | Grouped vesicles on the eyelid or lid margin
They are NOT always present; absence of vesicles does NOT exclude it |
| STI conjunctivitis | Often more severe and associated with prolonged mucopurulent discharge
|
Conjunctivitis vs keratitis
- Conjunctivitis is inflammation of the conjunctiva and is usually less serious, typically causing redness, irritation/grittiness and discharge, with normal vision and no significant pain or photophobia.
- Keratitis is inflammation/infection of the cornea and is potentially sight-threatening, suggested by eye pain, photophobia, reduced visual acuity, and contact lens use.
See the Infective Keratitis article for more information.
Complications
Adenoviral conjunctivitis can cause epidemic keratoconjunctivitis
- A highly contagious conjunctivitis with corneal involvement
- 30–50% patients develop sub-epithelial infiltrates which can cause persistent visual loss and light sensitivity
Bacterial conjunctivitis (esp. gonococcal conjunctivitis) can cause keratitis, especially in those who wear contact lenses and are immunocompromised
Investigation and Diagnosis
Infective conjunctivitis is primarily a clinical diagnosis based on clinical features (see above).
Do not routinely take swabs (for viral PCR – adenovirus and HSV + bacterial culture), consider if:
- In primary care, if the person does not require referral to ophthalmology but fails to respond to initial treatment
- In more severe or specific cases, swabbing is considered urgent and is typically performed in secondary care or upon urgent ophthalmological referral:
- Corneal involvement
- Gonococcal infection
Management
Refer for urgent assessment by ophthalmology if there is ANY of the following:
- Severe disease (e.g. corneal ulceration, significant keratitis, presence of pseudomembrane)
- Recent intra-ocular surgery
- Suspected gonococcal or chlamydial conjunctivitis
- Suspected herpes simplex conjunctivitis
- Suspected peri-orbital or orbital cellulitis
- Conjunctivitis associated with a severe systemic condition e.g. RA or immunocompromised
- Corneal involvement associated with soft contact lens use
Viral Conjunctivitis (Non-Herpetic)
Advise that most cases are self-limiting and usually resolve within 1-2 weeks without treatment
Avoid antibiotic prescription in viral conjunctivitis.
Advice on self-care measures to relieve symptoms:
- Cold compress around the eye area
- Bathing / cleaning the eyelids with cotton wool soaked in sterile saline or boiled and cooled water to remove any discharge
- Use of lubricating agents or artificial tears
Advice on the prevention of spread as infective conjunctivitis is contagious:
- Washing hands frequently with soap and water
- Use separate towels and flannels
- Avoid close contact with others
UKHSA does NOT recommend exclusion from school / nursery / childminders unless an outbreak or cluster of cases occurs.
Bacterial Conjunctivitis
Advise the person that most cases of bacterial conjunctivitis are self-limiting and resolve within 5–7 days without treatment
UKHSA does NOT recommend exclusion from school / nursery / childminders unless an outbreak or cluster of cases occurs.
Topical antibiotics may be used in bacterial conjunctivitis:
| Indications |
|
| Choice of antibiotics | Options for topical antibiotics:
To be continued for 48 hours after the infection has cleared |
Although topical chloramphenicol for eye use is NOT absolutely contraindicated in pregnancy, the BNF states that it should be ‘avoided unless essential‘.[Ref]
Oral chloramphenicol is contraindicated in pregnancy due to the risk (especially with use in the 3rd trimester) of ‘grey-baby’ syndrome.
Contact Lens Conjunctivitis
If there is NO suspected / confirmed corneal involvement (i.e. no corneal staining on topical fluorescein) and no other red flags → patient can be managed in primary care (instead of referring to ophthalmology)
Arrange urgent assessment by ophthalmology if there is corneal involvement associated with soft contact lens use, as this is considered a severe disease (e.g., significant keratitis or corneal ulceration).
- NICE: Have a low threshold for referral to ophthalmology if there is any suspicion of corneal involvement, as this is a potentially sight-threatening condition.
- In practice, most clinicians will refer all contact lens users with conjunctivitis to ophthalmology, in view of the risk of sight-threatening keratitis / ulceration.
Management:
- Stop contact lens use immediately and avoid until all symptoms have resolved
- Bathing / cleaning the eyelids with cotton wool soaked in sterile saline or boiled and cooled water to remove any discharge
- Consider topical antibiotic that covers gram -ve organisms, such as:
- Aminoglycoside (e.g. gentamicin)
- Fluoroquinolone (e.g. levofloxacin, moxifloxacin)