Are We Playing It Fast and Loose With the Serofast?

Four infants (one singleton and a set of triplets) born to mothers with serofast reactive plasma reagin at 1:4 to 1:8 were found to have congenital syphilis. Each mother had a history of receiving appropriate treatment for their syphilis stage at the time of diagnosis with benzathine penicillin G 2.4 million units intramuscularly weekly 3 times. Both exhibited a 4-fold decrease in their reactive plasma reagin titer. The singleton was asymptomatic but found to have long bone radiographic evidence for congenital syphilis. Of the triplets, one had laboratory abnormalities and a rash, while all 3 triplets had radiographic findings of congenital syphilis. All were treated with 10-14 days of intravenous penicillin G according to the Centers for Disease Control and Prevention treatment guidelines. These cases highlight that infants may be at risk for congenital syphilis, despite being classified as "congenital syphilis unlikely" according to current syphilis practice guidelines. A thorough maternal history and complete infant physical evaluation at birth is recommended for all neonates born to mothers diagnosed with and treated for syphilis. Close follow-up with repeat nontreponemal titers, as outlined by the Centers for Disease Control and Prevention and American Academy of Pediatrics guidelines, is recommended.