Trachoma
Trachoma is chronic conjunctival infection with Chlamydia trachomatis serovars A through C that, through repeated childhood reinfection and cicatricial scarring, causes trichiasis, corneal scarring, and blindness, and remains the world's leading infectious cause of preventable blindness. Diagnosis is clinical using the WHO simplified grading scheme, and management combines single-dose azithromycin with surgical correction of established trichiasis to prevent corneal damage.
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What this article covers
- Overview
A chronic, reinfection-driven conjunctival disease: trachoma is caused by Chlamydia trachomatis serovars A through C, which produce recurrent epithelial keratoconjunctivitis in childhood that, with…
- Epidemiology
Endemic in resource-limited, hyperendemic communities: trachoma is a global disease, concentrated where crowding, limited water access, and poor sanitation favor repeated childhood transmission.
- Risk factors
Repeated childhood reinfection: the central driver of trachomatous scarring; a single infection rarely causes blinding disease, but repeated cycles of infection and inflammation over years do.
- Pathophysiology
Direct infection of the conjunctival epithelium: Chlamydia trachomatis serovars A-C infect the tarsal conjunctiva, producing a follicular and papillary inflammatory response with lymphoid follicle formation.
- Clinical features
Active disease in childhood presents as follicular conjunctivitis: inflammation and lymphoid follicles are concentrated on the upper tarsal (inner eyelid) conjunctiva, often with mucopurulent…
- Differential diagnosis
Adult inclusion conjunctivitis (Chlamydia trachomatis serovars D-K): chronic conjunctivitis with mild mucopurulent discharge in a sexually active adult, distinguished from trachoma by serovar, lack…
- Diagnosis
First, establish the diagnosis clinically using the World Health Organization (WHO) simplified trachoma grading system, which defines five signs on eyelid eversion and corneal examination: TF…
- Management
First, treat active disease (TF/TI) with a single oral dose of azithromycin: 20 mg/kg PO (maximum 1 g) as a single dose is first-line for individual treatment and for community mass drug administration in endemic areas.
- Complications
Corneal blindness: the end-stage, irreversible outcome of repeated corneal trauma from trichiasis; trachoma is the leading infectious cause of preventable blindness worldwide.
- Prognosis
Excellent for active disease treated before scarring develops: azithromycin clears active infection effectively, and vision is preserved if treatment interrupts the cycle before significant scarring accumulates.
- Prevention
Community mass azithromycin treatment in hyperendemic districts: single-dose azithromycin 20 mg/kg (max 1 g) distributed to the eligible population interrupts community transmission when…
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