To report a rare case of episcleritis as the only manifestation of neurosyphilis.

A 40-year-old female was referred to the outpatient clinic because of right episcleritis that was unchanged during the month of treatment. Her headache persisted, and slit lamp examination showed tortuous congestion of engorged episcleral vessels with swelling in the superior-temporal region of the right eye, but fundus and radiological studies showed normal findings. Serological tests were reactive for venereal disease research laboratory test, treponema pallidum hemagglutination assay test, and fluorescent treponemal antibody absorption test. Under the suspicion of persistent syphilis infection, cerebrospinal fluid examination was performed, and the diagnosis of neurosyphilis with episcleritis was diagnosed. Treatment consisted of intravenous injections of 5 million IU penicillin G potassium every 4 hours for 14 days. The ocular inflammation resolved within the first week of treatment and did not recur.

We report a case of intractable episcleritis that required examination for syphilitic infection using serological and CSF tests, and the appropriate antimicrobial therapy for syphilis with follow-up examinations.