Congenital Syphilis: Symptoms, Types, Causes and Treatment

Congenital syphilis remains a significant and growing public health concern across the globe, affecting thousands of newborns each year. Although advances in prenatal care and screening have helped reduce cases in some regions, recent years have seen a resurgence in both high-income and low-income countries. This article provides a comprehensive, evidence-based overview of congenital syphilis—highlighting its symptoms, types, causes, and treatment—drawing on the latest clinical research and expert recommendations.

Symptoms of Congenital Syphilis

Congenital syphilis can be a challenging diagnosis due to its wide range of symptoms and the fact that many infants are asymptomatic at birth. Early recognition is crucial for initiating life-saving treatment and preventing long-term complications.

Symptom	Description	Frequency/Notes	Sources
Rash	Diffuse, may involve palms and soles	Common in early presentation	1 2 4
Anemia	Low red blood cell count	Frequently observed; up to 57% in some cohorts	2 3 7
Hepatosplenomegaly	Enlarged liver and/or spleen	Multisystem involvement; often with abnormal labs	1 2 3
Neurologic Signs	Aseptic meningitis, pseudoparalysis	May present as fever, limited movement	1 4
Skin Peeling	Desquamation of hands, feet, body	Distinctive but not always present	2
Abnormal Labs	Elevated liver enzymes, bilirubin, low albumin	Indicates liver involvement	2 3
Dental/Bone Changes	Abnormal teeth, bone lesions	More common in late or untreated cases	3

Table 1: Key Symptoms

Overview of Symptom Presentation

Many infants with congenital syphilis show no symptoms at birth. When symptoms do develop, they can appear from a few weeks up to several months after delivery, sometimes leading to a delayed diagnosis that increases the risk of complications 1 4 10. Classic symptoms such as rash (often involving palms and soles), anemia, hepatosplenomegaly, and skin peeling are commonly reported in early disease. Signs may be subtle and easily mistaken for other conditions, emphasizing the importance of clinical vigilance, especially in infants with unexplained symptoms 1 2 4.

Cutaneous and Hematologic Findings

• Rash: One of the hallmark features, but can be minimal or absent. When present, the rash is often diffuse and may include blisters or crusted papules, particularly on the palms and soles 1 2 4.
• Anemia: Over half of affected infants may develop anemia, which can be severe and contribute to other complications 2 3.
• Skin Peeling: Noted in about one-third of cases, particularly involving the hands, feet, and sometimes the entire body 2.

Visceral and Laboratory Abnormalities

• Hepatosplenomegaly: Enlargement of the liver and spleen is frequently observed and often accompanied by abnormal liver function tests, such as elevated aminotransferase and bilirubin levels, and decreased albumin 1 2 3.
• Lab Findings: Laboratory abnormalities are common, including increased white blood cell counts (monocytosis), anemia, and abnormal liver function markers 1 2.

Neurological and Musculoskeletal Signs

• Aseptic Meningitis: Some infants present with fever and signs of central nervous system involvement, such as irritability or seizures 1.
• Parrot Pseudoparalysis: Limited movement of limbs due to painful osteochondritis, a classic but less common sign 4.
• Dental/Bone Changes: These typically appear later and can include Hutchinson’s teeth and bone lesions, especially in untreated or late-diagnosed cases 3.

Asymptomatic Cases

More than half of infants exposed to syphilis may have no symptoms at birth, making routine screening of mothers and infants vital for early detection and prevention of severe outcomes 10 11.

Types of Congenital Syphilis

Congenital syphilis is broadly categorized based on the timing of symptom onset and the specific clinical manifestations. Understanding these types helps clinicians anticipate potential complications and tailor interventions.

Type	Onset/Timing	Key Features	Sources
Early	Birth to 2 years	Rash, hepatosplenomegaly, anemia, bone changes, neurologic involvement	1 2 3 4 10
Late	After 2 years	Dental abnormalities, bone deformities, neurologic sequelae	3 12
Asymptomatic	No symptoms	Detected by serologic testing only	10 11 12

Table 2: Major Types of Congenital Syphilis

Early Congenital Syphilis

• Timing: Symptoms develop from birth up to 2 years of age, with most cases presenting by 3-14 weeks 1 2 4.
• Clinical Manifestations: Early disease is characterized by multisystem involvement, including rash, hepatosplenomegaly, anemia, neurologic signs (such as aseptic meningitis), and bone changes (periostitis, pseudoparalysis) 1 2 3 4.
• Importance: Early recognition and treatment are critical to prevent progression to late disease and permanent sequelae.

Late Congenital Syphilis

• Timing: Symptoms appear after 2 years of age, sometimes not until adolescence 3 12.
• Clinical Manifestations: Late manifestations are the result of prolonged, untreated infection and include:
  • Dental changes (Hutchinson’s teeth)
  • Interstitial keratitis (eye inflammation)
  • Bone deformities (saber shins, saddle nose)
  • Neurologic complications (deafness, intellectual disability) 3 12
• Current Relevance: Classic late findings have become less common in settings with routine screening and early treatment but remain a risk in settings with delayed or missed diagnosis 12.

Asymptomatic Congenital Syphilis

• Definition: Infants have no clinical signs but test positive on serologic screening.
• Prevalence: Over 50% of affected infants are asymptomatic at birth, highlighting the critical role of routine maternal and neonatal testing 10 11 12.
• Significance: Asymptomatic infants can still develop complications without timely intervention, underscoring the need for universal screening and follow-up.

Causes of Congenital Syphilis

Understanding the causes and risk factors for congenital syphilis is essential for prevention and public health planning. The primary driver is maternal infection with Treponema pallidum, but numerous factors can influence whether transmission occurs.

Cause/Risk Factor	Mechanism/Impact	Prevention Approach	Sources
Maternal Syphilis Infection	Vertical transmission	Prenatal screening, treatment	5 6 9 13
Late Maternal Diagnosis	Infection undetected in pregnancy	Early/Repeat screening	5 6 13
Inadequate Maternal Treatment	Persistent infection	Ensure complete therapy	10 11 12
Lack of Prenatal Care	Missed testing/treatment	Improve access	5 9 10
High Maternal Titer	Increased transmission risk	Aggressive management	6
Socioeconomic Barriers	Reduced healthcare access	Public health support	9 11

Table 3: Main Causes and Risk Factors

Maternal Infection and Vertical Transmission

• Treponema pallidum: The causative bacterium is transmitted from mother to fetus primarily via the placenta at any stage of pregnancy 9.
• Transmission Risk: Highest during primary and secondary syphilis, with rates up to 100% if untreated 5.
• Global Burden: Over 1 million infants are born with congenital syphilis annually worldwide 10 13.

Timing and Adequacy of Maternal Care

• Late Diagnosis: Maternal syphilis diagnosed late in pregnancy (after 36 weeks) significantly increases the risk of fetal infection, as there is insufficient time for treatment to prevent transmission 6.
• Inadequate Treatment: Failure to receive or complete standard penicillin therapy during pregnancy allows Treponema pallidum to persist and cross the placenta 10 12.

Gaps in Prenatal Care and Screening

• Missed Opportunities: Women who do not access timely prenatal care or are not screened for syphilis are at highest risk of transmitting the infection to their infants 5 9.
• Seronegative Window: Rarely, women infected late in pregnancy may have negative serologic tests at first screening, leading to missed diagnoses 1 7.
• Socioeconomic Factors: Migrant status, poverty, and lack of health insurance are associated with higher rates of late or missed diagnosis 6 9 11.

Prevention Strategies

• Universal Screening: Early and repeated screening of all pregnant women, especially those at high risk, is essential 5 13 14.
• Immediate Treatment: On-site testing and immediate penicillin treatment can dramatically reduce cases 10 11.

Treatment of Congenital Syphilis

Treatment of congenital syphilis is straightforward and highly effective when delivered promptly, but effective management requires early identification, appropriate therapy, and careful follow-up.

Treatment	Administration	Outcome/Follow-up	Sources
Penicillin (IV/IM)	Standard of care	High cure rate, improves symptoms	1 2 10 12
Early Intervention	Treat before symptoms	Prevents complications, normal outcomes	2 10 13
Symptom Management	Supportive care	Address anemia, liver dysfunction	2 12
Maternal Treatment	During pregnancy	Prevents fetal infection	10 11 14

Table 4: Main Treatment Approaches

Standard Therapy

• Penicillin: The gold standard is parenteral penicillin (intravenous or intramuscular), typically administered for 10 days 1 2 10 12.
  • No documented resistance to penicillin in Treponema pallidum.
  • Alternative regimens are limited and less effective.
• Symptomatic Infants: Prompt initiation of penicillin resolves most symptoms, including rash, anemia, and liver dysfunction 1 2.
• Asymptomatic Infants: Treatment decisions may be based on maternal serology, infant laboratory values, and clinical findings 12.

Importance of Early Treatment

• Improved Prognosis: Early and adequate therapy can reverse most acute symptoms and prevent late complications, including neurologic and skeletal sequelae 2 10 13.
• Delayed Treatment: Increases the risk of permanent damage and classic late manifestations 12.

Management of Special Cases

• CNS Involvement: Infants with neurologic symptoms require a regimen that penetrates the central nervous system, such as intravenous penicillin G 12.
• Treatment Failures: Rare but reported, highlighting the need for close follow-up and repeat serologic testing 12.
• Maternal Therapy: Pregnant women with syphilis must receive appropriate penicillin treatment to prevent vertical transmission; non-penicillin regimens are not reliable for fetal protection 10 11 14.

Public Health and Systemic Approaches

• Decentralized Screening: Bringing testing and treatment to community and primary care settings increases early detection 10 11.
• Guideline Implementation: Following national and international protocols ensures uniform, evidence-based care for both mothers and infants 14.

Conclusion

Congenital syphilis is a preventable but persistent threat to maternal and child health. Despite significant advances in screening and treatment, resurgence in many regions underscores the need for vigilance and public health commitment. Key takeaways from this article include:

• Symptoms: Range from asymptomatic to severe multisystem disease, with rash, hepatosplenomegaly, anemia, and neurologic involvement as common features 1 2 3 4.
• Types: Early, late, and asymptomatic forms, each with distinct clinical implications 1 3 10 12.
• Causes: Primarily maternal infection with Treponema pallidum, compounded by gaps in prenatal care, late diagnosis, and inadequate treatment 5 6 9 10 11 13.
• Treatment: Timely administration of penicillin is highly effective, with early detection critical to prevent long-term complications 1 2 10 12 13 14.

Continued efforts to improve access to prenatal care, universal screening, and timely treatment are essential to eliminate congenital syphilis as a public health problem.