Disorders of the Conjunctiva: Conjunctivitis, Trachoma, Pterygium and Other Conditions

Scope. The conjunctiva is a visible, vascular mucous membrane, so many systemic, infectious, allergic, traumatic and neoplastic processes first appear as a “red eye.” This resource brings together the major conjunctival disorders, the history and examination needed to separate a simple conjunctivitis from sight-threatening disease, and a safe management pathway for emergency and primary-care learners. It expands the supplied teaching slides with clinical reasoning, public-health practice and referral thresholds.

Learning objectives

• Describe conjunctival anatomy, physiology and the clinical meaning of follicles, papillae, chemosis and injection.
• Classify infectious, allergic/immune, irritative, degenerative, haemorrhagic, traumatic and neoplastic disorders.
• Take a focused red-eye history and perform an examination that does not miss keratitis, uveitis, acute glaucoma or orbital disease.
• Give appropriate first aid, infection-control advice, treatment principles, safety-netting and referral.
• Recognise trachoma and other conditions in which prevention and community action protect vision.

1. Anatomy and physiology

The conjunctiva is a thin, transparent mucous membrane lining the posterior eyelids and covering the anterior sclera. It is continuous with the epithelium of the eyelid margin and joins the corneal epithelium at the limbus.

Goblet cells produce mucins that allow the aqueous tear layer to spread over the cornea. Conjunctival vessels provide immune surveillance and become dilated in inflammation. Lymphatics drain to preauricular and submandibular nodes. The conjunctiva is therefore a barrier, a lubricating surface and an immunological organ, not merely a “covering.”

2. The red-eye approach: triage before labels

2.1 Focused history

• Time course: sudden (minutes to hours), acute (days), recurrent or chronic (weeks/months).
• Laterality: unilateral onset that spreads to the other eye suggests contagious viral disease; bilateral simultaneous symptoms suggest allergy, irritant exposure or systemic disease.
• Vision: ask what has changed, whether it is corrected by blinking, and whether there is a field defect, halos or diplopia. Reduced acuity is a red flag.
• Pain and photophobia: itch and gritty discomfort favour conjunctiva; deep pain, marked photophobia or pain when light is shone in the unaffected eye suggests cornea, uvea or glaucoma.
• Discharge: watery (viral, allergic, irritant), mucoid/stringy (allergy), mucopurulent (bacterial) or copious hyperpurulent discharge (gonococcal emergency).
• Exposure and risk: sick contacts, school or household outbreak, swimming pool, dust/chemical splash, cosmetics, topical medicines, contact lenses, sexual exposure, newborn age, trauma and retained foreign body.
• Medical context: atopy, asthma/eczema, autoimmune disease, HIV or other immunosuppression, diabetes, anticoagulants, recent surgery, sexually transmitted infection and prior herpes.
• Recurrence or scarring: recurrent episodes, trichiasis, photophobia and declining vision require assessment for trachoma, cicatrising conjunctivitis or ocular-surface disease.

2.2 Examination sequence

1. Check general appearance, fever, facial/orbital swelling, vesicles and ability to open the eye.
2. Measure and document visual acuity in each eye separately, with usual correction and a pinhole if available.
3. Inspect pupils for size, reactivity and a relative afferent pupillary defect; assess ocular motility and diplopia.
4. Use a bright light to compare diffuse conjunctival injection with a deeper violaceous ciliary flush around the limbus.
5. Inspect lids and lashes; look for vesicles, crusting, ectropion, entropion, trichiasis and swelling. Evert the upper lid when a tarsal foreign body is suspected and there is no open-globe concern.
6. Characterise discharge, chemosis, follicles (round, pale elevations) and papillae (polygonal elevations with a central vessel).
7. Instil fluorescein when appropriate and examine with cobalt-blue light: epithelial defects, dendritic lesions, ulcers, foreign-body tracks and Seidel leakage must be identified.
8. Examine cornea, anterior chamber and lens. A hazy cornea, hypopyon, cells/flare or irregular pupil is an ophthalmic emergency.
9. Palpate preauricular and submandibular nodes. A tender preauricular node supports viral, chlamydial or severe bacterial disease.
10. Measure intraocular pressure only when it is safe and an open globe has been excluded; never press on a suspected penetrating injury.

3. Infectious conjunctivitis

3.1 Viral conjunctivitis

Adenoviruses cause highly contagious pharyngoconjunctival fever and epidemic keratoconjunctivitis (EKC). It usually begins in one eye and reaches the other within days. Watery discharge, gritty discomfort, follicular reaction, preauricular lymphadenopathy, sore throat and fever are typical. EKC may involve the cornea and cause prolonged photophobia and reduced vision.

• Transmission: hands, towels, respiratory droplets and contaminated examination equipment. Virus can persist on surfaces.
• Examination: watery discharge, follicles, chemosis, tender preauricular node and sometimes punctate keratitis or subepithelial infiltrates.
• Management: hand hygiene, separate towels, avoid eye touching, clean discharge with clean water or saline, lubricating drops and cool compresses. Stop contact lenses and eye cosmetics until completely recovered.
• Antibiotics: do not treat routine viral disease; they do not shorten adenoviral illness and can cause allergy or resistance.
• Steroids: topical corticosteroids may temporarily improve severe inflammation but can prolong adenovirus, worsen herpes or fungal infection, raise intraocular pressure and mask corneal disease. They require ophthalmic supervision.
• Return to activity: follow local infection-control policy; avoid close contact while tearing and discharge are prominent, especially in outbreaks.

Herpes simplex conjunctivitis/keratoconjunctivitis is often unilateral, with vesicles on the lid or nose, follicular conjunctivitis and a branching dendritic corneal ulcer. Do not use topical steroid without specialist direction. Arrange urgent ophthalmic review for antiviral treatment and corneal assessment.

Herpes zoster ophthalmicus causes a painful unilateral vesicular rash in the ophthalmic trigeminal distribution. Lesions on the tip of the nose, severe pain, photophobia or visual symptoms increase concern for ocular involvement. Start systemic antiviral therapy promptly according to the current local protocol and arrange same-day eye review; never delay referral while waiting for the rash to evolve.

3.2 Bacterial conjunctivitis

Common organisms include Staphylococcus, Streptococcus, Haemophilus and Moraxella. Typical features are acute redness, gritty discomfort and mucopurulent discharge that re-accumulates after wiping. The eyelids may be stuck together on waking, but visual acuity and corneal examination should remain normal.

• Clean crusts gently with sterile saline or cooled boiled water and wash hands before and after touching the eye.
• Contact lenses must be removed; discard the current lens case and seek review because bacterial keratitis can progress rapidly.
• Many uncomplicated cases are self-limited, but a clinician may prescribe a topical antibiotic when discharge is significant, the patient is high risk, or local guidance recommends it. Use one recommended agent correctly and complete the advised course; avoid sharing drops.
• Reassess if there is no clear improvement within 48–72 hours, if pain/photophobia or reduced vision develops, or if symptoms recur repeatedly.

Neonatal conjunctivitis (ophthalmia neonatorum) occurs in the first 28 days. Gonococcal disease is a sight-threatening emergency; chlamydial disease can coexist with pneumonia. Any newborn with purulent discharge, swollen lids or corneal involvement needs same-day hospital assessment, microbiological sampling and systemic therapy per neonatal/STI guidance. Do not delay referral for a routine “pink-eye” prescription.

3.3 Chlamydial adult inclusion conjunctivitis

Chronic unilateral or bilateral follicular conjunctivitis lasting more than two to three weeks, mucopurulent discharge, preauricular nodes and failure of routine topical antibiotics should prompt testing for Chlamydia trachomatis. Manage with systemic therapy and partner notification under the current STI guideline; topical treatment alone is inadequate. Ask sensitively about genital symptoms and test for other STIs.

4. Trachoma

Trachoma is chronic infection with ocular C. trachomatis, spread by hands, eye-seeking flies and contaminated cloths. Repeated infection produces conjunctival follicles and intense inflammation, followed by scarring, entropion, trichiasis, corneal abrasion and blindness.

The public-health SAFE strategy is Surgery for trichiasis, Antibiotics for active infection, Facial cleanliness and Environmental improvement (water, sanitation and fly control). Trachoma control is a community intervention, not only an individual prescription.

5. Allergic and immune-mediated conjunctivitis

5.1 Seasonal and perennial allergic conjunctivitis

Intense bilateral itching is the key symptom. Watering, chemosis, stringy mucus, sneezing and a history of atopy support the diagnosis. Seasonal disease follows pollen exposure; perennial disease may be related to dust mites, mould, animal dander or indoor irritants.

• Reduce exposure, avoid rubbing, use cool compresses and preservative-free lubricants.
• A clinician may recommend a topical antihistamine/mast-cell stabiliser or another agent in the local formulary. Correct technique and regular use during exposure are more effective than intermittent rubbing and vasoconstrictor drops.
• Severe, persistent, unilateral or vision-threatening symptoms require ophthalmic review to exclude vernal disease, keratitis or another diagnosis.

5.2 Vernal and atopic keratoconjunctivitis

Vernal disease affects children and young people, often in warm climates. Severe itch, photophobia, thick ropy discharge and large upper-tarsal “cobblestone” papillae or limbal Horner–Trantas dots are characteristic. Atopic keratoconjunctivitis occurs in patients with eczema or atopy and may scar the cornea. Both can cause shield ulcers and permanent visual loss. Avoid eye rubbing, treat the allergic component under specialist guidance and refer promptly when photophobia, corneal staining or reduced acuity is present.

5.3 Giant papillary, toxic and cicatrising conjunctivitis

• Giant papillary conjunctivitis: large papillae in contact-lens wearers or around ocular prostheses; stop lens wear, improve hygiene and arrange review.
• Medication/toxic conjunctivitis: burning, redness and follicular response after repeated topical medicines or preservatives; stop the suspected irritant only with clinical advice and substitute a safer regimen.
• Stevens–Johnson syndrome, ocular cicatricial pemphigoid and chemical injury: epithelial sloughing, severe pain, symblepharon or scarring are emergencies. Protect the ocular surface and obtain urgent ophthalmic and systemic care.

6. Degenerative and structural disorders

6.1 Pinguecula

A pinguecula is a yellow-white, slightly raised conjunctival degeneration near the nasal or temporal limbus that does not grow onto the cornea. Ultraviolet exposure, wind and dust contribute. Lubricants, protective eyewear and a hat reduce irritation. It is not an infection; excision is rarely needed unless recurrent inflammation or diagnostic uncertainty exists.

6.2 Pterygium

A pterygium is a triangular fibrovascular conjunctival growth that crosses the limbus onto the cornea. It may cause foreign-body sensation, redness, astigmatism and visual-axis obstruction. Document its size, corneal involvement, symptoms and progression. Reduce ultraviolet and dust exposure and use lubricants. Ophthalmology may excise a progressive, visually significant, repeatedly inflamed or cosmetically distressing lesion; recurrence is reduced by meticulous surgery and postoperative follow-up.

6.3 Other benign lesions

Conjunctival concretions are small, hard keratin deposits under the lid and can abrade the cornea. Retention cysts are clear, translucent lesions. Dermolipoma is a soft, congenital superotemporal mass. Conjunctivochalasis is redundant conjunctiva that disrupts the tear meniscus. Symblepharon is an adhesion between palpebral and bulbar conjunctiva after burns, trauma or cicatrising inflammation. Do not excise a lesion in primary care without diagnosis; document size, colour, vascularity and growth and refer when uncertain.

7. Subconjunctival haemorrhage

A sharply demarcated bright-red patch under the conjunctiva is usually painless and does not reduce vision. Minor trauma, coughing, vomiting, heavy lifting, hypertension, diabetes, anticoagulants and spontaneous vessel rupture may contribute. It commonly resolves over one to two weeks, sometimes changing colour as it clears.

• Check visual acuity, pupils, ocular motility and the cornea; ask about trauma and bleeding elsewhere.
• Do not lance or patch it. Lubricants may relieve mild irritation.
• Check blood pressure and review anticoagulants or bleeding risk with the prescribing clinician; do not stop essential anticoagulation independently.
• Refer if recurrent, extensive, associated with pain/vision loss, follows significant trauma, occurs with proptosis or has systemic bleeding features.

8. Conjunctival neoplasia: do not miss a changing lesion

Conjunctival intraepithelial neoplasia/squamous-cell carcinoma may appear as a gelatinous, leukoplakic or vascularised lesion near the limbus. Melanoma may be a new or enlarging pigmented mass; lymphoma can appear as a painless salmon-pink patch. HIV, immunosuppression, ultraviolet exposure and HPV increase risk for some lesions. A lesion that grows, bleeds, becomes irregular, is highly vascular, fails to respond to “conjunctivitis” treatment or is associated with lymphadenopathy needs urgent ophthalmic assessment and biopsy planning. Never destroy or repeatedly steroid-treat an undiagnosed mass.

9. Practical management pathway

1. Stabilise and protect: irrigate chemical exposures immediately, remove contact lenses, provide clean gauze/shield for trauma and avoid pressure on a possible open globe.
2. Document baseline: visual acuity, pain score, pupils, motility, laterality, discharge, corneal findings, fluorescein result, nodes and relevant exposures.
3. Control spread: handwashing, no shared towels or cosmetics, clean equipment between patients and stay away from school/work according to local infection-control advice during contagious discharge.
4. Use targeted therapy: supportive care for viral disease; clinician-selected topical antibiotic for appropriate bacterial cases; systemic STI treatment for gonococcal/chlamydial disease; antiallergic treatment and exposure control for allergy; specialist therapy for corneal, cicatrising or neoplastic disease.
5. Safety-net: return immediately for worsening pain, photophobia, reduced vision, increasing swelling, fever, corneal spot, new vesicles, inability to open the eye or no improvement within the expected interval.
6. Follow up: document resolution, adherence, contact-lens restart, partner/household management and referral completion.

10. Nursing, community and prevention responsibilities

• Perform hand hygiene before and after every eye examination; use gloves for purulent discharge and clean instruments according to infection-control policy.
• Teach caregivers to wipe from the inner canthus outward with a clean swab, using a fresh swab for each pass and each eye.
• Teach correct drop technique, medication spacing, storage and completion of prescribed therapy.
• Identify children with recurrent trachoma, trichiasis or visual difficulty and link them to eye-health programmes.
• Promote face washing, safe water, sanitation, fly control, clean towels, protective eyewear, ultraviolet protection and prompt care after chemical exposure.
• Ask about domestic violence or occupational exposures when the history is inconsistent with findings; document objectively and follow safeguarding policy.

11. Applied emergency cases

Case 1: Watery red eye in a household outbreak

A 19-year-old has unilateral gritty discomfort, watery discharge, a tender preauricular node and a normal cornea. The other eye becomes red two days later. This is most consistent with adenoviral conjunctivitis. Give hygiene and supportive-care advice, stop contact lenses, assess visual acuity and safety-net for photophobia or reduced vision. Antibiotics and unsupervised steroids are not routine.

Case 2: Copious pus and corneal risk

A young adult presents with severe lid swelling and pus that returns immediately after wiping. Treat as hyperacute gonococcal conjunctivitis until proved otherwise: protect staff, irrigate, obtain urgent samples, involve ophthalmology and sexual-health services, and administer systemic therapy according to the current protocol. A topical-only prescription is unsafe.

Case 3: Itchy child with photophobia

A child with eczema has bilateral severe itching, ropy mucus and large upper-lid papillae. Vernal/atopic keratoconjunctivitis is likely. Check acuity and fluorescein, stop rubbing, use protective eyewear and arrange prompt ophthalmic review because shield ulcer and corneal scarring can permanently reduce sight.

Case 4: Red eye after chemical splash

Do not wait for visual acuity, history or a referral letter. Begin copious irrigation immediately, remove contaminated contact lenses, evert lids during irrigation if safe, measure ocular surface pH after irrigation and transfer urgently for specialist assessment. Do not patch or instil steroid without ophthalmic direction.

12. Self-test

1. Which symptom most strongly favours allergic conjunctivitis over bacterial disease?
2. Name four red flags that make a red eye an emergency.
3. Why is hyperacute gonococcal conjunctivitis dangerous?
4. What does SAFE mean in trachoma control?
5. Why should a steroid-containing eye drop not be started in an undiagnosed red eye?
6. How do follicles differ from papillae clinically?
7. What advice reduces transmission of adenoviral conjunctivitis?
8. When should a pterygium or conjunctival mass be referred?

Answers

1. Prominent bilateral itching, often with atopy and watery/stringy discharge.
2. Examples include reduced vision, severe pain, marked photophobia, corneal opacity/ulcer, abnormal pupil, proptosis, contact-lens red eye, chemical injury, penetrating trauma, neonatal purulent discharge and hyperpurulent discharge.
3. N. gonorrhoeae can invade through intact epithelium and rapidly cause corneal ulceration or perforation.
4. Surgery for trichiasis, Antibiotics, Facial cleanliness and Environmental improvement.
5. Steroids can worsen herpes/fungal disease, prolong viral infection, raise intraocular pressure and mask a sight-threatening diagnosis.
6. Follicles are round pale lymphoid elevations without a central vessel; papillae are polygonal elevations with a central vascular core.
7. Handwashing, no shared towels/cosmetics, clean equipment, avoid touching/rubbing and follow local exclusion advice while discharge is active.
8. If it grows, encroaches on the visual axis, causes astigmatism or recurrent inflammation, or is pigmented, vascular, irregular, bleeding or diagnostically uncertain.

Key takeaways

• Always document visual acuity before calling a red eye conjunctivitis.
• Itch suggests allergy; watery discharge and a preauricular node suggest viral disease; mucopurulent discharge suggests bacterial disease; copious hyperpurulent discharge is an emergency.
• Pain, photophobia, corneal findings or reduced vision shift the differential toward keratitis, uveitis, glaucoma, trauma or orbital disease.
• Trachoma is preventable blindness: treat active disease, correct trichiasis and improve hygiene and environment.
• Never use steroid eye drops casually, and never delay irrigation for a chemical injury.

References and further reading

• Supplied teaching slides: Diseases of Conjunctiva.
• American Academy of Ophthalmology: Conjunctivitis Preferred Practice Pattern.
• EyeWiki: Conjunctivitis.
• Merck Manual Professional: Pinguecula and Pterygium.
• Royal Children’s Hospital: Acute red eye guideline.