TRACHOMA

BASICS

Description

• Trachoma is a chronic follicular conjunctivitis caused by Chlamydia trachomatis.
• Repeated ocular infection, particularly during childhood, produces chronic inflammation and progressive conjunctival scarring that can ultimately cause entropion, trichiasis, corneal damage, and blindness.
• In non-endemic areas, genital strains of C. trachomatis may be transmitted from the genital tract to the eye, producing inclusion conjunctivitis.
• Active infection is predominantly a disease of young children, whereas the consequences of repeated infection—scarring, trichiasis, and blindness—are mainly seen in adults.

EPIDEMIOLOGY

• Trachoma is associated particularly with poor, remote, rural communities where there is inadequate sanitation and limited access to clean water.
• Historically, hyperendemic regions have included parts of Africa, Asia, Central and South America, Australia, and the Middle East.
• Transmission occurs from the ocular and nasal secretions of infected individuals through:
• Hands and close personal contact
• Shared towels or other fomites
• Eye-seeking flies
• Transmission is particularly intense among young children and their caregivers.
• Boys and girls are affected approximately equally during childhood.
• In adulthood, women may be affected 2–6 times more frequently, largely because of repeated exposure while caring for infected children.
• Trachoma has historically affected tens of millions of people and is an important infectious cause of preventable blindness.

RISK FACTORS

The major risk factor is residence in a trachoma-endemic community.

Important environmental and social risk factors include:

• Overcrowding
• Poor facial and personal hygiene
• Limited availability of clean water
• Inadequate sanitation
• High density of flies
• Poor disposal of human and animal feces
• Close proximity to livestock
• Dry, dusty environments
• Recurrent bacterial or viral conjunctivitis
• Repeated exposure to infected children

Ocular infection with genital C. trachomatis strains is particularly associated with sexually active adolescents and young adults and produces inclusion conjunctivitis.

GENERAL PREVENTION

Prevention depends heavily on reducing transmission within affected communities.

Important measures include:

• Daily facial washing, particularly in children
• Improved personal hygiene
• Reliable access to clean water
• Proper latrine use
• Appropriate disposal of human and animal feces
• Refuse disposal
• Reduction of fly populations
• Health education
• Reduction of overcrowding where possible

Community health workers and school teachers can reinforce these measures in endemic areas.

PATHOPHYSIOLOGY

C. trachomatis has a predilection for conjunctival epithelial cells.

Repeated infections cause recurrent conjunctival inflammation. Over many years:

Repeated infection → chronic conjunctivitis → conjunctival fibrosis → eyelid deformity → entropion → trichiasis → corneal trauma → ulceration/scarring → blindness

Entropion

The eyelid turns inward.

Trichiasis

The eyelashes turn inward and repeatedly rub against the cornea.

Continued mechanical trauma produces:

• Corneal epithelial abrasion
• Ulceration
• Inflammation
• Superficial vascularization
• Corneal pannus
• Corneal haze
• Scarring
• Permanent visual impairment or blindness

ETIOLOGY

The causative organism is Chlamydia trachomatis, an obligate intracellular bacterium.

Serovars

• A, B, Ba, C → endemic trachoma
• D–K → genital chlamydial infection and inclusion conjunctivitis

A useful distinction is:

A–C = trachoma

D–K = genital/inclusion conjunctivitis

DIAGNOSIS

History

Endemic trachoma and inclusion conjunctivitis may initially present as mild conjunctivitis.

Many patients are asymptomatic. Others may develop:

• Ocular irritation
• Conjunctival inflammation
• Mucopurulent discharge
• Dry eyes
• Eyelid abnormalities
• Foreign-body sensation from trichiasis
• Progressive visual impairment

Longstanding trachoma may produce ocular dryness secondary to damage to the lacrimal ducts and lacrimal gland.

In adults, important historical clues include:

• Current or previous residence in an endemic area
• Recurrent conjunctivitis
• Progressive eyelid changes
• Inward-growing eyelashes
• Visual complaints

Neonatal chlamydial conjunctivitis

Neonatal disease tends to have a more acute onset and can produce profuse mucopurulent discharge.

PHYSICAL EXAMINATION

In endemic areas, trachoma is principally a clinical diagnosis.

The upper eyelid should be everted, and the upper tarsal conjunctiva and cornea carefully examined under adequate illumination and magnification.

Active disease

Children characteristically develop follicles on the upper tarsal conjunctiva.

These follicles represent focal collections of inflammatory tissue.

Chronic cicatricial disease

Repeated inflammation leads to conjunctival fibrosis and scarring.

Important classic findings include:

Arlt’s line

A horizontal line of conjunctival scarring along the superior palpebral/tarsal conjunctiva.

Herbert’s pits

Small limbal depressions produced by healed trachomatous follicles.

Corneal pannus

Superficial corneal inflammation accompanied by leukocytic infiltration and neovascularization.

Progression may therefore be:

Follicles → conjunctival scarring → Arlt’s line → entropion/trichiasis → pannus → corneal opacity → blindness

INCLUSION CONJUNCTIVITIS

Inclusion conjunctivitis caused by genital strains of C. trachomatis may produce:

• Conjunctivitis
• Follicular inflammation
• Discrete corneal infiltrates
• Punctate epithelial erosions
• Mild superficial corneal vascularization

A considerable proportion of affected adults have a concomitant genital chlamydial infection, even though many have no genital symptoms.

Therefore, affected patients and their sexual partners should be evaluated and systemically treated when indicated.

Failure to treat sexual partners increases the risk of reinfection and recurrent ocular disease.

DIAGNOSTIC TESTS AND INTERPRETATION

Trachoma is commonly diagnosed clinically in endemic regions, but laboratory testing can demonstrate C. trachomatis.

Diagnostic methods include:

• Giemsa-stained conjunctival smears
• Immunofluorescent staining
• Cell culture
• DNA-based testing
• Nucleic-acid amplification techniques

Detection of the organism provides definitive evidence of infection.

DIFFERENTIAL DIAGNOSIS

Other causes of conjunctivitis should be considered, including:

• Viral conjunctivitis
• Other bacterial conjunctivitis
• Parasitic infection
• Fungal infection

Important causes of neonatal conjunctivitis include:

• Chlamydia trachomatis
• Neisseria gonorrhoeae
• Haemophilus influenzae
• Streptococcus pneumoniae
• Herpes simplex virus

TREATMENT

First Line

Azithromycin

The source describes:

Azithromycin 20 mg/kg orally as a single dose

as the treatment of choice for active trachoma.

Systemic treatment is particularly useful because it treats both ocular infection and infection at extraocular sites.

Neonatal Chlamydial Conjunctivitis

Neonates require systemic antimicrobial therapy, rather than topical treatment alone.

This is important because concomitant nasopharyngeal chlamydial infection is common and untreated infection may subsequently produce chlamydial pneumonia.

Alternative Therapy

Topical tetracycline

The source describes:

Tetracycline ophthalmic ointment 1% twice daily for at least 6 weeks

or intermittent courses for 5 consecutive days each month for 6 months.

Other systemic alternatives

The source also lists:

• Doxycycline 100 mg PO twice daily for 21 days
• Tetracycline 250 mg PO four times daily for 14 days

Tetracyclines should be avoided when contraindicated, including in young children.

COMMUNITY TREATMENT

Individual therapy alone is insufficient in highly endemic communities because patients are repeatedly exposed to infected household and community contacts.

Mass antibiotic administration has therefore been used to reduce the community reservoir of infection.

The source describes community-wide treatment when active disease is sufficiently prevalent among children, followed by repeated treatment and subsequent reassessment.

WHO SAFE STRATEGY

The central public-health approach to trachoma control is easily remembered as SAFE:

S — Surgery

Surgery for trachomatous trichiasis/in-turned eyelids.

A — Antibiotics

Antimicrobial therapy, particularly oral azithromycin, to eliminate active C. trachomatis infection.

F — Facial cleanliness

Regular face washing, especially in young children, to reduce ocular and nasal secretions and transmission.

E — Environmental improvement

Measures include:

• Improved access to safe water
• Better sanitation
• Proper disposal of human and animal feces
• Latrine use
• Fly control
• Improved environmental hygiene

Thus:

SAFE = Surgery + Antibiotics + Facial cleanliness + Environmental improvement

SURGERY / OTHER PROCEDURES

Antibiotics eradicate active infection but cannot reverse established cicatricial eyelid deformity.

Patients with trichiasis therefore require corrective surgery.

Bilamellar tarsal rotation

Bilamellar tarsal rotation is an important surgical procedure for trachomatous trichiasis.

The operation redirects the eyelashes away from the cornea, reducing continuing corneal trauma and helping preserve vision.

Access to surgery may be limited in endemic regions because of:

• Lack of patient awareness
• Limited availability of trained personnel
• Cost
• Transportation difficulties
• Insufficient healthcare resources

ONGOING CARE

Follow-Up Recommendations

Patients require monitoring for:

• Recurrent active infection
• Persistent or recurrent trichiasis
• Progressive conjunctival scarring
• Corneal ulceration
• Corneal opacity
• Visual deterioration

Old trachoma may occasionally relapse, including after inappropriate use of topical corticosteroids.

PATIENT MONITORING

In communities undergoing mass antibiotic treatment, children should be reassessed clinically after completion of the community treatment program.

The source describes reassessment after approximately 3 years.

When prevalence has fallen sufficiently, management may transition from mass community treatment toward treatment of affected individuals and their household contacts.

PATIENT EDUCATION

Community education should emphasize:

• Regular facial washing
• Keeping children’s faces clean
• Fly control
• Adequate use of available water
• Latrine use
• Proper waste disposal
• Reducing exposure to animal and human feces
• Environmental sanitation

Patients with trichiasis should be educated about the benefits of corrective eyelid surgery before irreversible corneal damage occurs.

GENITAL INFECTION AND PARTNER MANAGEMENT

A substantial proportion of adults with chlamydial inclusion conjunctivitis have simultaneous genital chlamydial infection.

Importantly, many have no genital symptoms.

Patients with inclusion conjunctivitis should therefore undergo appropriate evaluation for genital infection.

Their sexual partners should also be evaluated and treated when indicated.

This is important because failure to treat the partner creates a reservoir for reinfection.

Untreated partner → reinfection → recurrent inclusion conjunctivitis

PROGNOSIS

The prognosis is generally good when infection is recognized and treated early.

The major determinant of long-term visual outcome is the cumulative burden of repeated infection and inflammation.

Repeated episodes progressively increase the risk of:

Scarring → entropion → trichiasis → corneal injury → irreversible blindness

Thus, preventing reinfection is as important as treating an individual episode.

COMPLICATIONS

The most important complications result from chronic cicatricial disease.

1. Entropion and trichiasis

Conjunctival scarring causes the eyelid to turn inward, bringing the eyelashes into contact with the cornea.

2. Corneal ulceration

Continuous eyelash abrasion damages the corneal epithelium and can produce corneal ulceration.

3. Corneal scarring and vascularization

Repeated trauma and inflammation cause:

• Corneal pannus
• Neovascularization
• Corneal opacity
• Permanent scarring

These changes can culminate in severe visual impairment or blindness.

4. Persistent inclusion conjunctivitis

Untreated inclusion conjunctivitis can persist for prolonged periods—from weeks to much longer periods.

5. Conjunctival scarring

Chronic inclusion conjunctivitis can itself produce conjunctival scarring. The source particularly associates scarring with prolonged inappropriate treatment using topical glucocorticoids.

6. Recurrent ocular infection

Recurrent inclusion conjunctivitis is especially likely when the patient’s sexual partner remains untreated.

Therefore, treatment must address both the ocular disease and the underlying genital reservoir when present.

HIGH-YIELD SUMMARY

Organism: Chlamydia trachomatis

Trachoma serovars: A, B, Ba, C

Inclusion conjunctivitis/genital serovars: D–K

Main reservoir in endemic communities: infected young children

Transmission: hands + fomites/towels + flies + ocular/nasal secretions

Characteristic active lesion: upper tarsal conjunctival follicles

Arlt’s line: linear conjunctival scar

Herbert’s pits: healed limbal follicles

Pannus: superficial corneal inflammation + neovascularization

Major mechanism of blindness:

Repeated infection → scarring → entropion → trichiasis → corneal ulceration/scarring → blindness

Treatment of active trachoma: oral azithromycin

Established trichiasis: surgery

Public-health strategy: SAFE

Surgery

Antibiotics

Facial cleanliness

Environmental improvement

Adult inclusion conjunctivitis: always think of concomitant genital chlamydia and an untreated sexual partner as a source of reinfection.