Conjunctivitis, Chlamydial (adult inclusion conjunctivitis)


The microorganism Chlamydia trachomatis is an obligate intracellular parasite (i.e. it cannot replicate outside a host cell)

  • Serotypes A-C cause trachoma, the leading cause of infectious blindness worldwide
  • Serotypes D-K are responsible for Ophthalmia Neonatorum (see Clinical Management Guideline on Ophthalmia Neonatorum ) and adult inclusion conjunctivitis (this Guideline) (named for the intracytoplasmic [inclusion] bodies seen in Giemsa-stained conjunctival scrapings)
  • many patients (up to 70%) have a concurrent genital infection (may be asymptomatic)

Predisposing factors

Most common in young adulthood (15-35 years)
Sexual activity leading to genital infection with C. trachomatis:

  • 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)
(the majority of cases are unilateral)

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 adenovirus keratoconjunctivitis, HSK, molluscum contagiosum

Management by optometrist

Practitioners should recognise their limitations 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
(NB even if diagnosis appears beyond doubt, do not commence specific treatment before referral as other STDs 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 by ophthalmologist

Laboratory testing to confirm diagnosis
Liaison with Genito-Urinary Clinic, which will exclude other STDs 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

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 

Plain language summary

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). 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. Most people with chlamydial infection will be cured if they take their antibiotics correctly.

Conjunctivitis, Chlamydial (adult inclusion conjunctivitis)
Version 14
Date of search 15.10.20
Date of revision 18.12.20
Date of publication 20.08.21
Date for review 14.10.22
© College of Optometrists 

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