Trachoma is a chronic conjunctivitis caused by Chlamydia trachomatis and is characterized by progressive exacerbations and remissions. It is the leading cause of preventable blindness worldwide. Initial symptoms are conjunctival hyperemia, eyelid edema, photophobia, and lacrimation. Later, corneal neovascularization and scarring of the conjunctiva, cornea, and eyelids occur. Diagnosis is usually clinical. Treatment is with topical or systemic antibiotics.
Trachoma is endemic in resource-limited parts of North Africa, the Middle East, the Indian subcontinent, Australia, and Southeast Asia, affecting 1.9 million people. It is also the cause of about 1.4% of blindness worldwide (1). The causative organism is Chlamydia trachomatis (serotypes A, B, Ba, and C).
In the United States, trachoma is rare, occurring occasionally among American Indians and immigrants. The disease occurs mainly in children, particularly those under the age of 10 (2, 3). Older children and adults are much less susceptible because of increased immunity and better personal hygiene.
Trachoma is highly contagious in its early stages and is transmitted by eye-to-eye contact, hand-to-eye contact, eye-seeking flies, or the sharing of contaminated articles (eg, towels, clothes, eye makeup).
General references
1. Trachoma: World Health Organization. Published October 21, 2024. Accessed January 15, 2025.
2. Delelegn D, Tolcha A, Beyene H, Tsegaye B. Status of active trachoma infection among school children who live in villages of open field defecation: a comparative cross-sectional study. BMC Public Health. 2021;21(1):2051. Published 2021 Nov 9. doi:10.1186/s12889-021-12106-8
3. Mekonnen J, Kassim J, Ahmed M, Gebeyehu N. Prevalence of active trachoma and associated factors among children 1-9 years old at Arsi Negele Town, West Arsi Zone, Oromia Regional State, Southern Ethiopia. PLoS One. 2022;17(10):e0273808. Published 2022 Oct 7. doi:10.1371/journal.pone.0273808
Symptoms and Signs of Trachoma
Trachoma usually affects both eyes.
Five stages are described in the World Health Organization grading system (1):
Trachomatous inflammation–follicular (TF): Characterized by 5 or more follicles in the upper tarsal conjunctiva
Trachomatous inflammation–intense (TI): Characterized by pronounced inflammatory thickening of the tarsal conjunctiva that obscures more than half of the normal deep tarsal vessels
Trachomatous scarring (TS): Characterized by scarring in the tarsal conjunctiva
Trachomatous trichiasis (TT): Characterized by at least 1 eyelash rubbing the globe
Corneal opacity (CO): Characterized by easily visible corneal opacity over the pupil
This photo shows several small follicles and intense inflammation in the upper tarsal conjunctiva consistent with trachomatous inflammation (follicular and intense types).
WESTERN OPHTHALMIC HOSPITAL/SCIENCE PHOTO LIBRARY
This photo shows scarring of the upper inner eyelid and cornea. The superior quarter of the cornea is opacified because of scarring.
© Springer Science+Business Media
In this photo, the cornea is scarred, and there is lower eyelid trichiasis.
© Springer Science+Business Media
This photo shows several small follicles and intense inflammation in the upper tarsal conjunctiva consistent with trachomatous inflammation (follicular and intense types).
WESTERN OPHTHALMIC HOSPITAL/SCIENCE PHOTO LIBRARY
This photo shows scarring of the upper inner eyelid and cornea. The superior quarter of the cornea is opacified because of scarring.
© Springer Science+Business Media
In this photo, the cornea is scarred, and there is lower eyelid trichiasis.
© Springer Science+Business Media
Rarely, corneal neovascularization regresses completely without treatment, and corneal transparency is restored. With treatment and healing, the conjunctiva becomes smooth and grayish white.
Trachoma trichiasis results from recurrent infections with resultant chronic inflammation of the tarsal conjunctiva. Conjunctival scarring and trichiasis may eventually lead to corneal opacification and ultimately blindness. In a population survey in the Nile Delta of Egypt, 6.5% of adults had trichiasis; of those, 13% had visual impairment and 8% were blind (2).
Symptoms and signs references
1. Solomon AW, Kello AB, Bangert M, et al. The simplified trachoma grading system, amended. Bull World Health Organ. 2020;98(10):698-705. doi:10.2471/BLT.19.248708
2. Ezz al Arab G, Tawfik N, El Gendy R, Anwar W, Courtright P. The burden of trachoma in the rural Nile Delta of Egypt: a survey of Menofiya governorate. Br J Ophthalmol. 2001;85(12):1406-1410. doi:10.1136/bjo.85.12.1406
Diagnosis of Trachoma
Ocular examination
Diagnosis of trachoma is usually clinical because testing is rarely available in endemic areas. Lymphoid follicles on the tarsal plate or along the corneal limbus, linear conjunctival scarring, and corneal pannus are considered diagnostic in the appropriate clinical setting.
C. trachomatis can be isolated in culture or identified by nucleic acid amplification tests (NAAT) and immunofluorescence techniques, and testing should be done when it is readily available to confirm diagnosis and prevent disease progression in cases of diagnostic uncertainty (1). In the early stage, minute basophilic cytoplasmic inclusion bodies within conjunctival epithelial cells in Giemsa-stained conjunctival scrapings differentiate trachoma from nonchlamydial conjunctivitis (2). Inclusion bodies are also found in adult inclusion conjunctivitis, but the setting and developing clinical picture distinguish it from trachoma.
Palpebral vernal conjunctivitis appears similar to trachoma in its follicular hypertrophic stage, but symptoms are different, milky flat-topped papillae are present, and eosinophils (not basophilic inclusion bodies) are found in the scrapings.
Diagnosis references
1. Wei Y, Xu X, Wang L, et al. A suitable and efficient optimization system for the culture of Chlamydia trachomatis in adult inclusion conjunctivitis. Pathog Dis. 2024;82:ftae020. doi:10.1093/femspd/ftae020
2. Streeten BW, Streeten EA. "Blue-body" epithelial cell inclusions in conjunctivitis. Ophthalmology. 1985;92(4):575-579. doi:10.1016/s0161-6420(85)33998-2
Treatment of Trachoma
Antibiotics, preferably systemic but alternatively topical
Surgery for eyelid deformities and/or corneal opacity
SAFE (Surgery, Antibiotics, Facial cleanliness, Environmental improvement) program in endemic areas
The World Health Organization (WHO) recommends that individual or sporadic cases of trachomatous inflammation–follicular be treated topically (1). The WHO also recommends topical treatment for trachomatous inflammation–intense, but that systemic treatment should be considered. Trachomatous scarring alone does not require treatment until it progresses to cause trachomatous trichiasis.
For systemic treatment, a single oral dose of azithromycin 20 mg/kg (maximum 1 g) is 78 to 95% effective (For systemic treatment, a single oral dose of azithromycin 20 mg/kg (maximum 1 g) is 78 to 95% effective (2, 3). As an additional benefit, the use of oral azithromycin has been associated with a significant reduction in overall childhood mortality. Alternatives include erythromycin 500 mg twice daily for 14 days or doxycycline 100 mg twice a day for 10 days (not to be used in pregnant or breastfeeding patients or in children under the age of 8). ). As an additional benefit, the use of oral azithromycin has been associated with a significant reduction in overall childhood mortality. Alternatives include erythromycin 500 mg twice daily for 14 days or doxycycline 100 mg twice a day for 10 days (not to be used in pregnant or breastfeeding patients or in children under the age of 8).
For topical treatment, tetracycline 1% ointment to both eyes twice a day for 6 weeks can be used. For topical treatment, tetracycline 1% ointment to both eyes twice a day for 6 weeks can be used.
The WHO recommends eyelid surgery for trachomatous trichiasis. If opacity has advanced into the central cornea, it is considered the stage of corneal blindness. In resource-rich nations, a corneal transplant could restore vision. The procedure is complex, and the frequent and intense aftercare to prevent rejection and infection makes corneal transplant impractical for many patients in most resource-limited nations.
Trachoma control in endemic areas
The WHO has endorsed a 4-step program for control of trachoma in endemic areas. This program is known as SAFE (1):
Surgery to correct eyelid deformities (eg, entropion and trichiasis) that place patients at risk of blindness
Antibiotics to treat individual patients and mass administration to reduce the disease burden in the community
Facial cleanliness to reduce transmission from infected people
Environmental improvement (eg, access to potable water and improved sanitation) to reduce transmission of disease and reinfection of patients
Endemic trachoma has been dramatically reduced by using community-wide oral azithromycin in people older that 6 months of age in a single dose or in repeated doses (Endemic trachoma has been dramatically reduced by using community-wide oral azithromycin in people older that 6 months of age in a single dose or in repeated doses (1). However, reinfection due to re-exposure is common. Reinfections can be reduced with fly control; better access to clean water, washing, and sanitation; building more hygienic latrines; and moving livestock and latrines farther from family living quarters.
In hyperendemic areas, mass administration to the entire community older than 6 months of age a single oral dose of azithromycin 20 mg/kg (maximum 1 g), or tetracycline or erythromycin ophthalmic ointment applied twice daily for 5 consecutive days each month for 6 months has been effective as treatment and prophylaxis (In hyperendemic areas, mass administration to the entire community older than 6 months of age a single oral dose of azithromycin 20 mg/kg (maximum 1 g), or tetracycline or erythromycin ophthalmic ointment applied twice daily for 5 consecutive days each month for 6 months has been effective as treatment and prophylaxis (1, 4).
Treatment references
1. World Health Organization: Trachoma control: a guide for programme managers. Published 2006.
2. Bailey RL, Arullendran P, Whittle HC, Mabey DC. Randomised controlled trial of single-dose azithromycin in treatment of trachoma. Lancet. 1993;342(8869):453-456. doi:10.1016/0140-6736(93)91591-9
3. Evans JR, Solomon AW, Kumar R, et al. Antibiotics for trachoma. Cochrane Database Syst Rev. 2019;9(9):CD001860. Published 2019 Sep 26. doi:10.1002/14651858.CD001860.pub4
4. Xiong T, Yue Y, Li WX, et al. Effectiveness of azithromycin mass drug administration on trachoma: a systematic review. Chin Med J (Engl). 2021;134(24):2944-2953. Published 2021 Sep 16. doi:10.1097/CM9.0000000000001717
Key Points
Trachoma is a chronic, exacerbating, and remitting chlamydial conjunctivitis that is common among children under the age of 10 in certain resource-limited areas worldwide.
Manifestations develop in stages and include conjunctivitis, formation of tarsal follicles, thickening and scarring of tarsal conjunctiva, trichiasis, and corneal neovascularization and scarring.
Trachoma is the leading cause of preventable blindness worldwide.
Diagnosis is usually clinical, but standard methods to detect chlamydia can be done when available.
Treatment is with topical or systemic antibiotics.
For endemic areas, the World Health Organization also advocates corrective surgery, mass administration of antibiotics, facial cleanliness, and environmental interventions to reduce transmission.
