Inclusion conjunctivitis is an acute or subacute follicular conjunctivitis caused by Chlamydia trachomatis serotypes D–K. It is transmitted through sexual contact or via the birth canal. This condition commonly occurs in sexually active young adults and often involves both eyes. Chlamydia trachomatis primarily infects the male urethra and the female cervix, spreading to the conjunctiva through sexual contact or hand-to-eye transmission. Spread can also occur indirectly through swimming pools. Neonates may contract the infection during vaginal delivery. Clinically, inclusion conjunctivitis is classified into adult and neonatal forms.
Clinical Manifestations
Adult Inclusion Conjunctivitis
Symptoms typically develop in one or both eyes 1–2 weeks after contact with the pathogen. The condition is characterized by mild to moderate redness, ocular irritation, and mucopurulent discharge, though some patients may remain asymptomatic. Swelling of the eyelids occurs, along with marked conjunctival hyperemia. Follicles and varying degrees of papillary hypertrophy are observed on the tarsal conjunctiva and fornices, predominantly in the lower fornices. Preauricular lymphadenopathy is also common. Acute inflammation gradually subsides over 3–4 months, but conjunctival thickening and follicles can persist for 3–6 months before complete resolution.
Neonatal Inclusion Conjunctivitis
The incubation period is 5–14 days after birth, though signs may appear on the first day if there has been premature rupture of the membranes. The condition usually affects both eyes, initially presenting with watery or scant mucoid discharge. As the disease progresses, discharge becomes more abundant and purulent. Conjunctivitis may persist for 2–3 months, leading to whitish, shiny follicles. Severe cases may involve pseudomembrane formation and conjunctival scarring. While most neonatal Chlamydia conjunctivitis cases are mild and self-limiting, corneal scarring and neovascularization may develop in severe cases.
Diagnosis
The diagnosis is generally straightforward based on clinical presentation. Neonatal inclusion conjunctivitis requires differentiation from infections caused by Chlamydia trachomatis serotypes associated with trachoma and Neisseria gonorrhoeae.
Treatment
Chlamydia infections may affect the respiratory and gastrointestinal systems, making systemic treatment necessary. Infants and young children can be given oral erythromycin at a dose of 12.5 mg/(kg·d), administered in four divided doses for at least 14 days. Recurrent cases may require a repeated full course of treatment. The parents of affected infants should also receive systemic antibiotic therapy to address genitourinary infections. Adult patients may be treated with a single 1 g dose of oral azithromycin or with doxycycline at 100 mg twice daily for 7 days. Sexual partners of affected individuals should undergo examination and receive appropriate treatment.
Prognosis and Prevention
Education on hygiene, particularly regarding sexual health, is important for reducing transmission among young adults. High-quality prenatal care, including testing and treatment for genital Chlamydia infections, is critical for preventing neonatal infections.