The capital accounts for 75% of cases in the nationwide outbreak of the sexually transmitted infection.
That's over 10 times the amount of cases of the next county, which is Cork with 7% of the country's cases.
The latest figures show that between January 1st and April 30th of this year, 242 cases of syphilis were reported. Health authorities are calling for "urgent action."
2020 saw a decrease in cases from the previous year with 562 cases, down from 745 in 2019. But the latest figures have health officials concerned.
While syphilis mostly affects males, cases among females have risen 4.5% in 2018 to 9% in 2021.
"There is a potentially large undiagnosed reservoir of syphilis infection in Ireland due in part to the impact of COVID-19," health authorities said in a statement. "Syphilis is a very treatable sexually transmitted infection and early recognition and treatment are critical to preventing avoidable morbidity for those infected and onward transmission to others. If an infection remains untreated, it can cause serious health problems to the heart, brain, eyes and nervous system."
The statement warned that "Syphilis can also be passed from mother to foetus in utero, known as congenital syphilis."
Symptoms to watch out for include non itchy rashes; flu-like symptoms; hair loss; and sore eyes or blurring of vision.
The HSE advises that "All individuals with newly diagnosed syphilis should be referred to Genitourinary or Infectious Diseases services for assessment, treatment and follow up."
