T. pallidum can be transmitted by an infected mother to the fetus in utero. In untreated cases stillbirth occurs in 19% to 35% of reported cases, 25% of infants die shortly after birth, 12% are without symptoms at birth, and 40% will have late symptomatic congenital syphilis. The treponeme can cross the placenta at any time during pregnancy. Adequate therapy of the infected mother before the sixteenth week of gestation usually prevents infection of the fetus. Treatment after 18 weeks may cure the disease but not prevent irreversible neural deafness, interstitial keratitis, and bone and joint changes in the newborn. The fetus is at greatest risk when maternal syphilis is of less than 2 years’ duration. The ability of the mother to infect the fetus diminishes but never disappears in late latent stages.

Early congenital syphilis.

Early congenital syphilis is defined as syphilis acquired in utero that becomes symptomatic during the first 2 years of life. The fetal stigmata seen before the age of 2 years include eruptions characteristic of secondary syphilis, such as maculopapular rash and desquamating erythema of the palms and soles; hepatosplenomegaly; and jaundice. Bone and joint symptoms are common. Osteochondritis with the "sawtooth" metaphysis seen on radiographs and periostitis appear with tender limbs and joints. Rhinitis with highly infectious nasal discharge, nontender generalized adenopathy, alopecia, iritis, and failure to thrive occur less frequently.

Late congenital syphilis

Symptoms and signs of late congenital syphilis become evident after age 5 years. The average age at first diagnosis is 30 years. The most important signs are frontal bossae (bony prominences of the forehead) (87%), saddle nose (74%), short maxilla (83%), high arched palate (76%), mulberry molars (more than four small cusps on a narrow first lower molar of the second dentition), Hutchinson’s teeth (peg-shaped upper central incisors of the permanent dentition that appear after age 6 years) (63%), Higoumenakis sign (unilateral enlargement of the sternoclavicular portion of the clavicle as an end result of periostitis) (39%), and rhagades (linear scars radiating from the angle of the eyes, nose, mouth, and anus) (8%). Hutchinson’s triad (Hutchinson’s teeth, interstitial keratitis, and VIIIth nerve deafness) is considered pathognomonic of late congenital syphilis.