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See Chap. 83.



  • Trachoma is a chronic conjunctivitis caused by C. trachomatis serovars A, B, Ba, and C. Transmission occurs through contact with ocular discharge from infected pts, which is sometimes transferred by flies.
  • AIC is an acute eye infection occurring in adults exposed to infected genital secretions and in their newborns. This infection is caused by sexually transmitted C. trachomatis strains, usually serovars D–K.


Trachoma is a leading cause of preventable infectious blindness, with ~6 million pts having been affected. In the hyperendemic regions of northern and sub-Saharan Africa, the Middle East, and parts of Asia, the prevalence of trachoma is ~100% by the third year of life. Reinfection and persistent infection are common.

Clinical Manifestations

Both trachoma and AIC present clinically as conjunctivitis characterized by small lymphoid follicles in the conjunctiva, although trachoma usually starts insidiously before 2 years of age.

  • With progression of trachoma, there is inflammatory leukocytic infiltration and superficial vascularization (pannus formation) of the cornea.
    • Scarring eventually distorts the eyelids, turning lashes inward and abrading the eyeball (trichiasis and entropion).
    • The corneal epithelium eventually ulcerates, with subsequent scarring and blindness.
    • Destruction of goblet cells, lacrimal ducts, and glands causes dry-eye syndrome (xerosis), with resultant corneal opacity and secondary bacterial corneal ulcers.
  • AIC is an acute unilateral follicular conjunctivitis with preauricular lymphadenopathy and presents similarly to acute conjunctivitis due to adenovirus or HSV.
    • Corneal inflammation is evidenced by discrete opacities, punctate epithelial erosions, and superficial corneal vascularization.
    • Left untreated, the disease may persist for 6 weeks to 2 years.


Clinical diagnosis of trachoma is based on the presence of two of the following signs: lymphoid follicles on the upper tarsal conjunctiva, typical conjunctival scarring, vascular pannus, or limbal follicles.

  • Intracytoplasmic chlamydial inclusions are found in 10–60% of Giemsa-stained conjunctival smears from children with severe inflammation.
  • However, chlamydial nucleic acid amplification tests are more sensitive in detecting infection.


  • AIC responds to azithromycin (a single 1-g oral dose) or doxycycline (100 mg PO bid for 7 days). Treatment of sexual partners is needed to prevent ocular reinfection and chlamydial genital disease.


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Loscalzo, Joseph, et al., editors. "C. TRACHOMATIS INFECTIONS." Harrison's Manual of Medicine, 19th ed., McGraw Hill Inc., 2017. harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623257/all/C__TRACHOMATIS_INFECTIONS.
C. TRACHOMATIS INFECTIONS. In: Loscalzo J, Jameson JL, Longo DL, et al, eds. Harrison's Manual of Medicine. 19th ed. McGraw Hill Inc.; 2017. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623257/all/C__TRACHOMATIS_INFECTIONS. Accessed April 18, 2019.
C. TRACHOMATIS INFECTIONS. (2017). In Loscalzo, J., Jameson, J. L., Longo, D. L., Hauser, S. L., Fauci, A. S., & Kasper, D. L. (Eds.), Harrison's Manual of Medicine. Available from https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623257/all/C__TRACHOMATIS_INFECTIONS
C. TRACHOMATIS INFECTIONS [Internet]. In: Loscalzo J, Jameson JL, Longo DL, Hauser SL, Fauci AS, Kasper DL, editors. Harrison's Manual of Medicine. McGraw Hill Inc.; 2017. [cited 2019 April 18]. Available from: https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623257/all/C__TRACHOMATIS_INFECTIONS.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - C. TRACHOMATIS INFECTIONS ID - 623257 ED - Loscalzo,Joseph, ED - Jameson,J Larry, ED - Longo,Dan L, ED - Hauser,Stephen L, ED - Fauci,Anthony S, ED - Kasper,Dennis L, BT - Harrison's Manual of Medicine UR - https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623257/all/C__TRACHOMATIS_INFECTIONS PB - McGraw Hill Inc. ET - 19 DB - Harrison's Manual of Medicine DP - Unbound Medicine ER -