Conjunctivitis, Chlamydial


Chronic follicular conjunctivitis caused by the sexually transmitted microorganism Chlamydia trachomatis (serotypes D-K), an obligate intracellular parasite (i.e. it cannot replicate outside a host cell). Spread by direct contact or fomites.

Chlamydial conjunctivitis is also known as ‘adult inclusion conjunctivitis’ (named after the intracytoplasmic [inclusion] bodies seen in Giemsa-stained conjunctival scrapings).

Range in severity from mild to severe.

Predisposing factors

Most common in young adulthood (15-35 years)
Sexual activity leading to genital infection with C. trachomatis (up to 70% of cases of chlamydial conjunctivitis have a concurrent genital infection):

  • urethritis, cervicitis, prostatitis, proctitis (inflammation of the rectum), etc.; (may be asymptomatic)
  • increased prevalence of Chlamydial conjunctival infection in sexual partner(s) which may be asymptomatic

Symptoms of chlamydial conjunctivitis

History usually more than two weeks
Ocular gritty sensation and sticky discharge
Drooping upper lid(s) (often unilateral but may involve both eyes)

Signs of chlamydial conjunctivitis

Lid and other features

  • oedema +/- ptosis (‘mechanical’)
  • non-tender pre-auricular lymph node swelling (may or may not be present)

Conjunctival features

  • hyperaemia and chemosis
  • mucopurulent conjunctivitis
  • large follicles in upper and lower fornices (double eversion of lid needed to view upper fornix)
  • limbal and/or bulbar follicles may also be present

Corneal features

  • epithelial keratitis, usually superior
  • subepithelial infiltrates, similar to those seen in adenovirus KC
  • marginal infiltrates
  • superior pannus

(NB signs may be unilateral or asymmetrical or bilateral)

Differential diagnosis

Other causes of acute red eye such as allergic, viral or bacterial conjunctivitis.

Management by optometrist

Practitioners should work within their scope of practice, and where necessary seek further advice or refer the patient elsewhere

Non pharmacological

Advise against contact lens wear
(GRADE*: Level of evidence=low, Strength of recommendation=strong)


Symptomatic relief with ocular lubricants (drops for use during the day, unmedicated ointment for use at bedtime)
NB even if diagnosis appears beyond doubt, do not commence specific treatment before referral as other sexual transmitted infections (STIs) may also be present
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Management category

A3: first aid measures and urgent referral to ophthalmologist or GP with a view to onward referral to Genito-Urinary Clinic

Possible management in secondary care or local primary/community pathways where available

Additional guidance may be available

Laboratory testing to confirm diagnosis
Liaison with Genito-Urinary Clinic, which will exclude other STIs and advise on treatment of patient and partner(s).
Treatment with systemic antibiotics (e.g. single dose of azithromycin or a short course of doxycycline). Patients and sexual partners must be treated

Evidence base

*GRADE: Grading of Recommendations Assessment, Development and Evaluation (

Sources of evidence

Azari AA, Barney NP. Conjunctivitis: a systematic review of diagnosis and treatment. JAMA. 2013;310:1721-9

Lee WA, Chen CC. Adult inclusion conjunctivitis diagnosed by polymerase chain reaction and Giemsa stain. ID Cases. 2021;27:e01367.

Malamos P, Georgalas I, Rallis K, Andrianopoulos K, Georgopoulos G, Theodossiadis P, Vergados I, Markomichelakis NN. Evaluation of singledose azithromycin versus standard azithromycin/doxycycline treatment and clinical assessment of regression course in patients with adult inclusion conjunctivitis. Curr Eye Res. 2013;38(12):1198-206.

Mohamed-Noriega K, Mohamed-Noriega J, Valdés-Navarro MA, Cuervo-Lozano EE, Fernández-Espinosa MC, Mohamed-Hamsho J. Conjunctival infection with Chlamydia trachomatis in sexual partners of patients with adult inclusion conjunctivitis. Int Ophthalmol. 2015;35(2):179-85 


What is Chlamydial Conjunctivitis?

Chlamydia is one of the most common sexually transmitted infections (STIs) in the UK.

In the eyes, chlamydia can cause irritation, pain, swelling and discharge, usually affecting one eye only. Most patients who have chlamydial conjunctivitis will also have a genital infection (of which they may be unaware). 

How is Chlamydial Conjunctivitis managed?

It is important that these patients are referred urgently to the ophthalmologist, who will liaise with the genito-urinary medicine clinic where the patient can have a full STI investigation. Chlamydial infection is usually treated with antibiotics, which can be very effective. Patients’ sexual partners also may need treatment. Most people with chlamydial infection will be cured if they take their antibiotics correctly.

Conjunctivitis, Chlamydial (adult inclusion conjunctivitis)
Version 15
Date of search 12.02.23
Date of revision 23.03.23
Date of publication 26.05.23
Date for review 11.02.25
© College of Optometrists 

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