MSD Manual

Please confirm that you are a health care professional

honeypot link

Adult Inclusion Conjunctivitis

(Adult Chlamydial Conjunctivitis; Swimming Pool Conjunctivitis)


Zeba A. Syed

, MD, Wills Eye Hospital

Reviewed/Revised Apr 2023

Adult inclusion conjunctivitis is caused by sexually transmitted Chlamydia trachomatis. Symptoms include chronic unilateral hyperemia and mucopurulent discharge. Diagnosis is clinical. Treatment is with systemic antibiotics.

Adult inclusion conjunctivitis, which makes up 1.8 to 5.6% of all cases of acute conjunctivitis, is caused by Chlamydia trachomatis serotypes D through K. In most instances, adult inclusion conjunctivitis results from sexual contact with a person who has a genital infection. Usually, patients have acquired a new sex partner in the preceding 2 months. Genital infections are present in up to 54% of males and 74% of females. Rarely, adult inclusion conjunctivitis is acquired from contaminated, incompletely chlorinated swimming pool water.

Symptoms and Signs of Adult Inclusion Conjunctivitis

Adult inclusion conjunctivitis has an incubation period of 2 to 19 days. Most patients have a unilateral mucopurulent discharge. The tarsal conjunctiva is often more hyperemic than the bulbar conjunctiva. Characteristically, there is a marked tarsal follicular response. Occasionally, superior corneal opacities and vascularization occur. Preauricular lymph nodes may be swollen on the side of the involved eye. Often, symptoms have been present for many weeks or months and have not responded to topical antibiotics.

Diagnosis of Adult Inclusion Conjunctivitis

  • Clinical evaluation

  • Laboratory testing

Chronicity (symptoms for > 3 weeks), mucopurulent discharge, marked tarsal follicular response, and failure of topical antibiotics differentiate adult inclusion conjunctivitis from other bacterial conjunctivitides Acute Bacterial Conjunctivitis Acute conjunctivitis can be caused by numerous bacteria. Symptoms are hyperemia, lacrimation, irritation, and discharge. Diagnosis is clinical. Treatment is with topical antibiotics, augmented... read more Acute Bacterial Conjunctivitis . Smears, bacterial cultures, and chlamydial studies should be done. Immunofluorescent staining techniques, nucleic acid amplification tests (NAAT), and special cultures are used to detect C. trachomatis. Smears and conjunctival scrapings should be examined microscopically and stained with Gram stain to identify bacteria and stained with Giemsa stain to identify the characteristic epithelial cell basophilic cytoplasmic inclusion bodies of chlamydial conjunctivitis.

Pearls & Pitfalls

  • If patients have symptoms of bacterial conjunctivitis plus a marked tarsal follicular response (often with mucopurulent discharge), symptoms for > 3 weeks, or failure to respond to topical antibiotics, do smears, bacterial cultures, and chlamydial studies.

Treatment of Adult Inclusion Conjunctivitis

  • Oral azithromycin or doxycycline

Azithromycin 1 g orally once only or either doxycycline 100 mg orally twice a day or erythromycin 500 mg orally 4 times a day for 1 week cures the conjunctivitis and concomitant genital infection. Sex partners also require treatment.

Key Points

  • Adult inclusion conjunctivitis is caused by Chlamydia trachomatis and is usually sexually acquired; in rare cases it can be acquired by swimming in a contaminated swimming pool.

  • The tarsal conjunctiva are usually more hyperemic than the bulbar conjunctiva; there is a marked tarsal follicular response.

  • Treat sex partners as well as the patient with oral azithromycin or doxycycline.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
quiz link

Test your knowledge

Take a Quiz!