Diagnosis and Treatment of
Adult Inclusion Conjunctivitis

BY WILLIAM TOWNSEND, O.D.
FEB. 1996

The most common cause of chronic follicular conjunctivitis is Chlamydia Trachomatis, an organism that is almost exclusively sexually transmitted. Keep this in mind when a patient's recalcitrant conjunctivitis does not respond to topical medications.

This 22-year-old white female suffered from an irritated, unilateral (left) red eye for several months. She reported a scant mucopurulent discharge that was variably present. She was seen by several primary care practitioners, each of whom treated the condition with a different topical antibiotic medication. These medications quieted the eye, but once the drops were discontinued, the redness and irritation returned. Best corrected vision was 20/20 in both eyes. Pupils, ocular motility and other neurologic tests were normal. Slit lamp evaluation showed clear corneas with injection and prominent follicles in the lower tarsus of the affected eye only. The anterior chambers were clear of cells and flare bilaterally. Eversion of the upper lid showed mild papillae OU. Palpation of the preauricular nodes showed adenopathy on the left side only. The patient denied any vaginal irritation or discharge. She stated that she had been dating a new boyfriend for about three months.

[THE HISTORY AND CLINICAL FINDINGS IN THIS CASE STRONGLY INDICATED ADULT INCLUSION CONJUNCTIVITIS, A SEXUALLY TRANSMITTED ORGANISM.]

The clinical findings and history in this case strongly indicated adult inclusion conjunctivitis (AIC). We instructed the patient's family physician to order a Chlamydiazyme test. The results confirmed our initial diagnosis of AIC.

DIAGNOSIS

AIC is caused by C. Trachomatis, an intracellular obligate parasite that, like viruses, depends on a host cell for reproduction. Among women, it can cause salpingitis, urethritis, cervicitis and pelvic inflammatory disease. Among men, it can cause urethritis, epidedymitis, prostatitis or Reiter's syndrome.

Sources estimate that 1 in 300 individuals with genital chlamydial infection will also develop ocular infection, probably due to hand-to-eye transfer. There is a high association of chlamydial infection with other venereal infections so it's advisable that patients with chlamydia get tested for other sexually transmitted diseases.

Among AIC patients, follicles in the lower tarsus and preauricular adenopathy are very common. Corneal involvement is limited and a superiorly located, coarse punctate keratitis is often present. Marginal and central infiltrates are also found in some patients. Unlike adenoviral disease, AIC frequently causes a superior micropannus, which helps in differential diagnosis. AIC patients are often prescribed antibiotics by doctors who diagnose bacterial conjunctivitis. The condition improves with topical drops but returns after the drops are discontinued.

Laboratory testing is extremely valuable in the diagnosis of AIC. The traditional lab test for this organism is the Chlamydiazyme test, an enzyme immunoassay with fairly good sensitivity (75 percent to 85 percent) but excellent specificity (98 percent). In other words, with this test, you may miss a few patients with the disease, but when the test reads positive, you can be relatively sure of the diagnosis. The Direct Fluorescent Antibody test uses an IgG antibody to directly detect C. Trachomatis in clinical specimens. While this is a very sensitive test it has poor specificity and will result in false positives because the IgG antibody is reactive to all Chlamydial species. If you really suspect AIC, order both tests.

TREATMENT

Treat AIC with oral antibiotics. The agent of choice is doxycycline with an initial dose of 200mg; thereafter, the dosage is 100mg P.O. b.i.d. for three weeks. Tetracycline 250mg P.O. q.i.d. is also an effective treatment. Erythromycin works best for patients who are allergic to tetracyclines, and pregnant or nursing women. Prescribe 250mg P.O. q.i.d. for three weeks. Obviously, it's essential to treat any sexual partners as well. CLS

Dr. Townsend is in private practice in Canyon, Texas, and is a consultant at the Amarillo VA Medical Center.