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 poverty-stricken parts of North Africa, the Middle East, the Indian subcontinent, Australia, and Southeast Asia. The causative organism is Chlamydia trachomatis (serotypes A, B, Ba, and C). In the US, trachoma is rare, occurring occasionally among Native Americans and immigrants. The disease occurs mainly in children, particularly those between the ages of 3 and 6. 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, handkerchiefs, eye makeup).
Symptoms and Signs
Trachoma usually affects both eyes. Four stages are described.
In stage 1, after an incubation period of about 7 days, conjunctival hyperemia, eyelid edema, photophobia, and lacrimation gradually appear, usually bilaterally.
In stage 2, after 7 to 10 days, small follicles develop in the upper tarsal conjunctiva and gradually increase in size and number for 3 or 4 wk. Inflammatory papillae appear on the upper tarsal conjunctiva. Corneal neovascularization begins, with invasion of the upper half of the cornea by loops of vessels from the limbus (called pannus formation). The phase of acute follicular/papillary hypertrophy and corneal neovascularization may last from several months to > 1 yr, depending on response to therapy.
In stage 3, the follicles and papillae gradually shrink and are replaced by bands of scar tissue. Without treatment, corneal scarring eventually occurs. The entire cornea may ultimately be involved, reducing vision. Secondary bacterial infection is common, contributing to scarring and disease progression.
In stage 4, the conjunctival scar tissue often causes entropion (often with trichiasis) and lacrimal duct obstruction. Entropion and trichiasis lead to further corneal scarring and neovascularization. The corneal epithelium becomes dull and thickened, and lacrimation is decreased. Small corneal ulcers may appear at the site of peripheral corneal infiltrates, stimulating further neovascularization.
Rarely, corneal neovascularization regresses completely without treatment, and corneal transparency is restored. With treatment and healing, the conjunctiva becomes smooth and grayish white. Impaired vision or blindness occurs in about 5% of people with trachoma.
Diagnosis 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. If diagnosis is uncertain, C. trachomatis can be isolated in culture or identified by PCR and immunofluorescence techniques. In the early stage, minute basophilic cytoplasmic inclusion bodies within conjunctival epithelial cells in Giemsa-stained conjunctival scrapings differentiate trachoma from nonchlamydial conjunctivitis. Inclusion bodies are also found in adult inclusion conjunctivitis (see Conjunctival and Scleral Disorders: 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.
For individual or sporadic cases, azithromycin 20 mg/kg (maximum 1 g) po as a single dose is 78% effective. Alternatives are doxycycline 100 mg bid or tetracycline 250 mg qid for 4 wk. In hyperendemic areas, tetracycline or erythromycin ophthalmic ointment applied bid for 5 consecutive days each month for 6 mo has been effective as treatment and prophylaxis. Endemic trachoma has been dramatically reduced by using community-wide oral azithromycin in a single dose or in repeated doses. Reinfection due to re-exposure is common among endemic areas. Better personal hygiene and environmental measures (eg, access to potable water) can reduce reinfection.
Eyelid deformities (eg, entropion and trichiasis) should be treated surgically.
Last full review/revision October 2012 by Melvin I. Roat, MD, FACS
Content last modified November 2012