Neurosyphilis, Ocular Syphilis and Otic Syphilis in Chicago, 2023

Syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum, has been rising in the United States since 2001. When the bacterium invades the central nervous system, eyes or ears — neurosyphilis, ocular syphilis and otic syphilis, together called NOO syphilis — it can cause meningitis, stroke, loss of movement or sensation, blindness and hearing loss. It can happen at any stage of infection: primary, secondary, latent or tertiary.

Data from the early and mid-2000s suggested NOO syphilis was found mostly among gay, bisexual and other men who have sex with men (MSM) and people with HIV, probably reflecting the syphilis trends of that time. In Chicago in 2019, 11 of 16 NOO cases were in MSM and nine were in people with HIV. In 2023, Chicago clinicians began reporting more NOO syphilis in heterosexual people without HIV, and the Chicago Department of Public Health checked whether that held citywide.

How cases were found

The health department searched its surveillance system for Chicago residents from January 1 to October 31, 2023, with cerebrospinal fluid results pointing to neurosyphilis (a reactive VDRL test, raised protein or raised white cell count), treatment with intravenous penicillin, or any recorded sign or symptom of NOO syphilis. It reviewed medical records against the 2018 Council of State and Territorial Epidemiologists case definitions, matched cases to HIV surveillance data, and compared them with 2019, leaving out the COVID-19 pandemic years, when cases were likely underreported.

What it found

Of 2,611 syphilis cases of all stages reported from January 1 to October 31, 2023, 689 (26.4%) were in people with HIV and 521 (20.0%) in MSM. Forty (1.5%) were NOO syphilis:

• 28 (70.0%) neurosyphilis, 24 (60.0%) ocular syphilis and 2 (5.0%) otic syphilis, with 14 patients having more than one type;
• ages 23 to 82 (median 46.5), compared with a median of 33 in 2019;
• 29 (72.5%) male and 26 (65.0%) Black or African American.

Among the 28 patients whose symptoms were recorded, the most common were decreased vision (60.7%), rash (35.7%) and sudden headache (32.1%). Eight of the 14 whose signs fit primary or secondary syphilis had abnormal spinal fluid tests. Symptoms were similar whether or not patients had HIV. All 11 women with NOO syphilis were among the patients without HIV.

What it means

In 2023, NOO syphilis in Chicago was found more often than in 2019 in people without HIV and in people who were not MSM. The authors urged clinicians to consider NOO syphilis even in patients without HIV who are not MSM, and called for better surveillance of these infections.

Sources

• Nham A, Holly T, Flores J, Kern D, Tabidze I. "Notes from the Field: Neurosyphilis, Ocular Syphilis, and Otic Syphilis — Chicago, January–October 2023." MMWR 2025;74(8).