oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
The term conjunctivitis refers to inflammation of the conjunctiva; associated corneal involvement gives rise to keratoconjunctivitis and eyelid involvement suggests blepharoconjunctivitis.
Inflammation can be infective or non-infective in origin and can be further subdivided into acute or chronic conjunctivitis. This is a worldwide condition that can affect any age group. There is no gender, ethnic or social preponderance. Although it is usually a reasonably minor problem, it can have a considerable impact on lost work time and, very occasionally, can result in permanent or sight-threatening sequelae.
If you see a conjunctival problem that is not conjunctivitis, refer to the separate article Conjunctival Problems for more about assessing the conjunctiva and for 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).
- Red eye - usually generalised, often bilateral.
- Irritation, grittiness and discomfort; significant pain suggests alternative diagnoses.
- Discharge - may be watery, mucoid, sticky or purulent depending on the cause.
- Photophobia - this suggests corneal involvement.
- Visual acuity unaltered - in conjunctivitis any alteration in vision should be minimal, related to tearing and discharge blurring the visual field; consider differential diagnosis if there is any significant visual loss.
- Conjunctival injection with dilated conjunctival vessels.
- Conjunctival chemosis (conjunctival oedema).
- Follicles or papillae.
- Corneal involvement (rarely): oedema, neovascularisation and punctate epithelial erosions.
If the aetiology is not obvious after a general history is taken, specifically ask about contact lens wear, trauma (including chemical and ultraviolet exposure) and symptoms and signs potentially related to systemic disease.
- Wear gloves if suspecting adenoviral infection - this is extremely contagious (and clean all equipment after use).
- Look for evidence of generalised malaise and preauricular lymph nodes.
- Check visual acuity.
- External eye: assess for evidence of orbital cellulitis, blepharitis, herpetic rash or nasolacrimal blockage.
- Conjunctiva: look at the pattern of congestion, discharge and for the presence of follicles or papillae.
- Papillae - these are formed when the conjunctival inflammation is effectively limited by fibrous septa, so giving rise to the appearance of vascular bulges, generally found on the upper tarsal conjunctiva. They can coalesce to form giant (cobblestone) papillae.
- Follicles - these are lymphoid collections and look like raised gelatinous pale bumps (like small grains of rice). They tend to be found on the lower tarsal conjunctiva and along the upper tarsal border.
- Cornea: is there evidence of corneal involvement? Staining is an essential part of the examination.
- Fundoscopy: this is necessary if you are unsure about the diagnosis.Look for clouding of the anterior chamber.
Generally, the diagnosis is rapidly made following history and examination but further investigations are warranted (referral to a specialist) in the following circumstances:
- Severe purulent discharge.
- Follicular conjunctivitis.
- Neonatal conjunctivitis.
- Unclear aetiology.
- Non-response to conventional treatment.
Differential diagnosis: conditions to rule out before diagnosing conjunctivitis
- 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. These symptoms suggest deeper inflammatory conditions of the eye.
- Glaucoma: check for reduced visual acuity, hazy cornea, fixed pupil and acute systemic malaise. Acute glaucoma is extremely painful and usually causes nausea and vomiting - it is unlikely to be confused with conjunctivitis.
- Herpes zoster ophthalmicus: signs include severe herpetic pain which can occur before the rash and the classical vesicular rash affecting the tip if the nose. There is commonly an associated conjunctivitis.
- Keratitis: this may be associated with conjunctivitis but can occur alone, often secondary to infection (be suspicious of this in contact lens wearers) - look for unilaterality, severe pain and photophobia. Keratitis may also occur over a raised pterygium, which can become dry, inflamed and sore.
- Scleritis and episcleritis: these are unilateral, with localised injection and aching (episcleritis) or an intense, boring pain (scleritis).
- Foreign body: this may not be remembered by the patient. If you can't find a foreign body but still strongly suspect this, double evert the lids after instilling topical anaesthetic or refer to the ophthalmology team.
- Trauma: may not always be remembered by the patient and can be mechanical or chemical. Remember, where there is trauma to the globe, and if there is a history of welding, grinding or drilling when particulate matter could have flown into the eye, consider the possibility of penetration of the globe and stain the eye to look for fluid leakage. Penetration of the globe which does not involve the corneal areas can be relatively asymptomatic.
Which type of conjunctivitis is this?
Conjunctivitis of different aetiologies can appear to present in a similar fashion so here are a few tips:
- Viral - often adenovirus, could also be herpes simplex virus (HSV).
- Bacterial - including gonococcus.
- Allergic/vernal atopic.
- Pediculosis (lice, crabs).
Chronic symptoms (>4 weeks)
- Molluscum contagiosum.
- Toxic reaction.
- Superior limbic keratoconjunctivitis.
If follicles are present
- Preauricular lymph nodes not present:
- Toxic conjunctivitis, molluscum, pediculosis.
- Preauricular lymph nodes present:
- With herpetic signs suggests HSV conjunctivitis.
- Without herpetic signs suggests adenoviral conjunctivitis or chlamydia.
If papillae are present
What kind of discharge is there?
- Severe purulent discharge, eyelid swelling: gonococcal infection.
- Scant purulent discharge: bacterial other than gonococcus.
- Watery discharge: allergic, atopic.
- Mucoid discharge: consider vernal conjunctivitis.
To find out more about infective conjunctivitis, see separate article Infective Conjunctivitis which covers:
- Simple bacterial conjunctivitis
- Gonococcal conjunctivitis
- Chlamydial conjunctivitis
- Adenoviral conjunctivitis
- Herpes simplex keratoconjunctivitis
- Herpes zoster ophthalmicus
- Molluscum contagiosum conjunctivitis
Other related separate articles include:
This refers to a group of inflammatory conditions affecting the conjunctiva. They lead to scarring, loss of function and, potentially, loss of sight. All should be referred urgently for ophthalmological review.
Causes of primary cicatricial conjunctivitis include:
- Ocular mucous membrane pemphigoid (OMMP) - thought to be a type II hypersensitivity reaction affecting the basement membrane of mucosal surfaces. Oral mucosa and conjunctiva are most commonly affected. Treatment is with topical steroids and antibiotics but the acute phase of the disease may warrant systemic immunosuppression.
- Erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis - these are acute vasculitides that may be different forms of the same disease, thought to result from a type III hypersensitivity response.
Causes of secondary cicatricial conjunctivitis include:
- Trauma: thermal, chemical and radiation trauma may all cause cicatrisation, as can surgery.
- Chronic and severe anterior blepharitis: the reduced tear film associated with blepharitis can cause chronic irritation and scarring.
- Drugs: may cause mild-to-severe irritation. Systemic drugs such as penicillamine and topical drugs (many, including timolol and pilocarpine) can have an effect.
- Inherited conditions: abnormalities of hair or teeth may suggest ectodermal dysplasia.
- Systemic problems: many can cause cicatricial conjunctivitis, including rosacea, Sjögren's syndrome and graft-versus-host disease.
- Neoplasia: unilateral disease may rarely represent sebaceous cell carcinoma, conjunctival intraepithelial neoplasia or squamous cell carcinoma. If in any doubt, refer for urgent ophthalmological opinion.
Floppy eyelid syndrome
This occurs most often in obese patients with sleep apnoea. Nocturnal eyelid ectropion results in conjunctival contact with bedding. It can occasionally lead to corneal scarring. There will be upper eyelid swelling and diffuse papillary reaction. There may be a pannus. Temporary relief can be achieved with lubricants and taping of the lid. Definitive treatment is surgical.
Giant papillary conjunctivitis
This is an irritant conjunctivitis which comes about gradually in response to prolonged contact lens wear, presence of ocular prosthesis or to exposed corneal sutures. It is characterised by papillary hypertrophy, a mucoid discharge and, in severe cases, ptosis. Treatment involves removal of the irritant, together with use of cool compresses, lubricants and topical mast cell stabilisers.
Parinaud's oculoglandular syndrome
This rare condition can arise as a result of cat scratch disease, tularaemia, sporotrichosis, tuberculosis, syphilis and infectious mononucleosis. It presents with generalised malaise and a unilateral conjunctivitis. It responds to treatment of the underlying cause.
Pediculosis (lice, crabs)
A unilateral/bilateral condition arising from eyelash colonisation by pubic lice. It gives rise to itching, and adult lice will be seen on the lids. Mechanical removal of the lice and their eggs needs to be carried out and an ophthalmic antimicrobial ointment used for the lashes in association with anti-lice treatment to the rest of the body (the patient and sexual partners).
Superior limbic keratoconjunctivitis
This is an uncommon, chronic condition which mainly affects women in their 50s with thyroid dysfunction. Patients complain of nonspecific conjunctivitis-type symptoms (foreign body sensation, burning, mucoid discharge) which wax and wane over many years before eventually resolving. There is thickening of the conjunctiva around the superior corneal limbus, and a corneal pannus. Punctate epithelial erosions may be present. Cool compresses, regular lubrication and, occasionally, anti-inflammatories are used.
Prolonged (>1 month) use of aminoglycosides, antivirals, drops with preservatives and inappropriate use of over-the-counter preparations containing vasoconstrictors may give rise to an irritant conjunctivitis. Diagnosis is made by exclusion. There will be conjunctival hyperaemia and follicles. Treatment is to discontinue the offending agent and use supportive measures (cool compresses, preservative-free lubricants) until symptoms settle.
Further reading & references
- Forrester JV, Dick AD, McMenamin PG, Lee WR; The Eye: Basic Sciences in Practice (3rd ed.) 2007, WB Saunders
- Handbook of Ocular Disease Management
- Care of the contact lens patient; American Optometric Association, 2006
- Conjunctivitis Preferred Practice Pattern; American Academy of Ophthalmology, 2013
- Morrow GL, Abbott RL; Conjunctivitis. American Family Physician Vol. 57/No. 4. February 15, 1998
- Azari AA, Barney NP; Conjunctivitis: a systematic review of diagnosis and treatment. JAMA. 2013 Oct 23;310(16):1721-9. doi: 10.1001/jama.2013.280318.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Olivia Scott
Dr Mary Lowth
Dr Helen Huins