A nurse is assessing a newborn whose mother tested positive for syphilis during pregnancy but did not receive adequate treatment. Which assessment finding would be most indicative of congenital syphilis in this newborn?

The scenario describes a newborn with a known risk factor for congenital syphilis: maternal infection with Treponema pallidum without adequate treatment. Congenital syphilis results primarily from the transplacental passage of the spirochete from mother to fetus, and can lead to a wide range of adverse outcomes, including premature delivery, stillbirth, and a diverse, often non-specific clinical presentation in the neonate [2,4]. The nurse's assessment must focus on identifying signs that are highly characteristic of this infection to facilitate prompt diagnosis and treatment.

Option 1: Copper-colored, maculopapular rash on palms and soles with desquamation. This is a classic and highly indicative cutaneous manifestation of early congenital syphilis. The rash is often described as a diffuse, copper-colored maculopapular eruption that characteristically involves the palms and soles, frequently followed by desquamation. This finding is a direct result of the hematogenous dissemination of T. pallidum and the host's inflammatory response in the skin. Its presence in a newborn with a known maternal history is a major clinical clue for congenital syphilis ^[4].

Option 2: Jaundice appearing within the first 24 hours after birth. While hepatomegaly and jaundice can be associated with congenital syphilis due to hepatic inflammation, jaundice manifesting within the first 24 hours of life is most concerning for pathologic hyperbilirubinemia, such as that caused by hemolytic disease of the newborn (e.g., Rh or ABO incompatibility). It is not the most specific or classic presenting sign for congenital syphilis.

Option 3: Respiratory distress with nasal flaring and grunting. Respiratory distress in a newborn is a non-specific finding with a broad differential, including transient tachypnea of the newborn, respiratory distress syndrome, sepsis, and pneumonia. Although congenital syphilis can present with a syphilitic pneumonitis (pneumonia alba), this is a less common and less specific isolated finding than the characteristic rash.

Option 4: Hypoglycemia with jitteriness and poor feeding. These signs are indicative of a metabolic or neurologic disturbance. While a severely affected infant with congenital syphilis may be lethargic and feed poorly, these symptoms are non-specific and more commonly point to common neonatal problems like hypoglycemia due to poor glycogen stores, sepsis, or hypoxic-ischemic encephalopathy.

The correct answer is the copper-colored rash on the palms and soles because it represents a direct mucocutaneous manifestation of disseminated treponemal infection. After T. pallidum crosses the placenta, it enters the fetal circulation, leading to widespread dissemination. The organism's predilection for the skin and mucous membranes results in the classic syphilitic rhinitis (snuffles) and the characteristic rash. The involvement of the palms and soles is a hallmark feature that distinguishes it from many other neonatal rashes. This finding is a key component of the clinical evaluation for infants born to mothers with syphilis, alongside other evaluations like long-bone radiographs and cerebrospinal fluid analysis to rule out central nervous system infection [1,2].

The diagnostic challenge in congenital syphilis is significant because most infected infants are asymptomatic at birth. When signs do appear, they can be subtle and non-specific. Therefore, recognizing pathognomonic findings like the palmar/plantar rash is critical. Diagnostic workup for an infant with suspected congenital syphilis involves both treponemal and nontreponemal tests, and newer methods like IgM immunoblotting or PCR can help identify an infant's own immune response to the infection, reflecting an in utero infection rather than passive transfer of maternal antibodies [1,3].