By Ethan Covey
A recent CDC report highlights increases in three types of syphilis—neurosyphilis, ocular syphilis and otic syphilis (NOO syphilis)—among heterosexual people and those without HIV in Chicago.
While NOO syphilis typically has been more prevalent among gay, bisexual, and men who have sex with men (MSM) and people with HIV, the findings showcase the importance of considering NOO syphilis, regardless of HIV status or sex of sexual partners (MMWR Morb Mortal Wkly Rep 2025;74[8]:140-143).
From Jan. 1 through Oct. 31, 2023, a total of 2,611 cases of syphilis were reported to the Chicago Department of Public Health (CDPH). A total of 40 NOO syphilis cases were reported, 67.5% of which occurred in people who were HIV-negative, compared with 43.8% in 2019. In the 82.5% of patients with NOO syphilis who reported their sex and that of their sexual partners, 54.5% were not MSM. This compares with 26.7% who were not MSM during 2019.
Among the 40 total cases of NOO syphilis, 70% were neurosyphilis, 60% ocular syphilis and 5% otic syphilis. The patients ranged in age from 23 to 82 years, 72.5% of them were male and most (65%) were non-Hispanic Black or African American. The most commonly reported symptoms, among the 70% of people for whom this information was available, were decreased vision (60.7%), rash (35.7%) and acute headache (32.1%).
According to the lead author of the report, Amy Nham, PharmD, a career epidemiology field officer at the CDPH, the rise in NOO syphilis cases is in line with increases seen in national syphilis trends.
“The trends of NOO syphilis often reflect the underlying syphilis epidemic, [and] the changes seen in Chicago in 2023 are similar to those at the national level,” she said.
At the national level, the large increase in syphilis cases among heterosexual populations, most of whom do not have HIV, have been caused by a range of factors, including:
- reductions in sexually transmitted infection (STI) services at the state and local level;
- increases in substance use, which has been linked to less safe sexual practices;
- social and economic conditions that make it harder for some groups to stay healthy;
- lack of insurance;
- decreasing condom use among some groups;
- stigma that may discourage people from seeking care or sharing risk factors for STIs; and
- geography.
Enhanced surveillance efforts are needed to better understand NOO syphilis trends, according to Dr. Nham.
“Additional study regarding the demographics and clinical characteristics of NOO syphilis in other parts of the country may help to support and refine this guidance,” she added. “More research on the frequency of NOO syphilis diagnosis based on the stage of syphilis (i.e., primary, secondary, tertiary, latent) would be helpful, as most clinicians may not consider NOO syphilis in patients with early stages of syphilis when, in actuality, NOO syphilis can occur at any stage of syphilis,” Dr. Nham said.
Dr. Nham reported no relevant financial disclosures.
