Syphilitic Retinitis: A Rare Presentation of a Resurgent Sexually Transmitted Infection in an HIV-Negative Individual

We present a rare presentation of isolated syphilitic retinitis in an HIV-negative man. A 47-year-old male presented to our ophthalmology center with complaints of blurred vision, pain, and redness in the left eye for the past seven days. The best corrected visual acuity for distance was 6/6 and best corrected near visual acuity for near was N6 in the right eye. The best corrected visual acuity for distance was finger counting at 1 m and best corrected near visual acuity for near was 1:32), the Treponema Pallidum Hemagglutination Assay was positive, and the patient tested negative for human immunodeficiency virus antibodies. Based on these findings, a diagnosis of syphilitic retinitis was made. The patient was given three doses of 2.4 million units of benzathine penicillin intramuscularly (once a week) and doxycycline 100 mg twice daily for the same period. After completion of treatment, the best corrected visual acuity for distance improved to 6/9 and the best corrected near visual acuity for near improved to N6 in the right eye, and the lesions in the eye resolved. The best corrected visual acuity for distance improved to 6/12 and the best corrected near visual acuity for near improved to N10 in the left eye. If a patient presents with unexplained ophthalmic findings such as uveitis, vitritis, or retinitis, then a diagnosis of syphilis should be considered even if the patient does not give a history of high-risk sexual behaviour. Thus, both the physician at the sexually transmitted infection clinic and the ophthalmologist should be aware of these symptoms and signs and consider this as a potential diagnosis. This will result in prompt investigations, appropriate diagnosis, and clinical management, and eventually prevent loss of vision.