Congenital Syphilis: Symptoms, Treatment & Prevention

Congenital syphilis is an infection caused by the bacterium Treponema pallidum and passed from mother to baby. It can lead to serious complications such as skin sores, deafness, blindness, premature birth, yellowing of the skin and eyes, miscarriage, and, in severe cases, death.

A baby can be exposed to congenital syphilis at any point during pregnancy or during delivery. It is more common when the mother has syphilis and did not receive treatment or was not treated correctly.

If congenital syphilis is suspected in a baby, the child should be evaluated by a pediatrician. Treatment, when needed, is mainly done with penicillin injections.

Main symptoms

The main symptoms of congenital syphilis are:

• Skin sores

• Yellowish skin

• Fever

• Irritation and cracks around the mouth, genitals, and anus

• Low weight and/or short length

• Enlarged liver or spleen

• Bone abnormalities

• Runny nose

In late congenital syphilis, the child may have hearing problems, deafness, blindness, intellectual disability, hydrocephalus, seizures, misshapen teeth, mucus around the anus and vagina, and scars around the mouth, genitals, and anus.

Based on the age when symptoms begin, congenital syphilis can be classified as early, when symptoms appear soon after birth or up to 2 years of age, or late, when they appear after 2 years of age.

Confirming a diagnosis

Congenital syphilis is diagnosed by an OB-GYN or a pediatrician after reviewing the mother’s and baby’s medical history and symptoms.

To confirm the diagnosis, the doctor may also order tests such as cerebrospinal fluid (CSF) analysis, microscopic evaluation of the baby’s nasal discharge, chest and long-bone X-rays, treponemal antibody blood tests, and a VDRL test, which is used to help diagnose syphilis.

Diagnosing congenital syphilis in a baby can be challenging because test results may appear positive due to antibodies transferred from the mother. Therefore, the diagnosis should be based on the mother’s medical history and treatment, as well as the newborn’s clinical signs, laboratory results, and imaging findings.

Treatment options

According to the CDC, penicillin G is the recommended treatment for congenital syphilis, and the specific regimen is chosen based on the infant’s evaluation findings and maternal treatment history.

Treatment for congenital syphilis depends on the baby’s age and whether the mother was treated.

1. Newborn of a mother with untreated or inadequately treated syphilis

This type of treatment is indicated when the mother did not receive treatment for syphilis or was treated inadequately. In these cases, treatment is done in one of the following ways:

• With a positive VDRL and/or clinical, radiologic, and/or hematologic changes, but no neurologic problems: injection of 50,000 IU/kg of aqueous crystalline penicillin G every 12 hours for 7 days, followed by 50,000 IU/kg of aqueous crystalline penicillin G every 8 hours after the first week, or procaine penicillin G 50,000 units/kg/dose every 24 hours by intramuscular injection for 10 days.

• With cerebrospinal fluid (CSF) abnormalities, or if it was not possible to collect CSF: give crystalline penicillin G injections for 10 days at a dose of 50,000 units/kg/dose every 12 hours during the first week of life and every 8 hours after the first week.

For a newborn with a negative VDRL and no clinical, radiologic, hematologic, or CSF changes, a single injection of 50,000 units/kg of benzathine penicillin G is recommended.

2. Newborn of a mother adequately treated for syphilis

When the mother has been treated adequately, the recommended treatment for the newborn includes:

• With a VDRL result higher than the mother’s and no CSF abnormalities: treat with crystalline penicillin G injections for 10 days at a dose of 50,000 units/kg/dose every 12 hours during the first week of life and every 8 hours after the first week; or treat with procaine penicillin G 50,000 units/kg/dose every 24 hours for 10 days. If the CSF is abnormal, only crystalline penicillin G should be used.

• With normal test results, no symptoms, and a negative VDRL that is equal to or lower than the mother’s: only medical follow-up is needed. If follow-up cannot be ensured, a single injection of benzathine penicillin G at a dose of 50,000 units/kg may be given.

In any of these situations, if treatment is interrupted for more than 24 hours, it is recommended to restart the entire treatment.

3. Babies older than 28 days

Treatment for babies older than 28 days who have symptoms and serologic test results suggestive of congenital syphilis is done with crystalline penicillin G injections every 4 hours at a dose of 50,000 IU/kg for 10 days, or with procaine penicillin G injections of 50,000 IU/kg every 12 hours.

Can congenital syphilis be cured?

Congenital syphilis can be cured with proper treatment. Although the infection is treated with antibiotics right away, follow-up blood testing and medical monitoring may continue for months to confirm that treatment was successful.

How to prevent

To help prevent congenital syphilis, it is essential to attend prenatal appointments regularly. According to the CDC, all pregnant people should be tested for syphilis at the first prenatal visit, and some should be tested again in the third trimester and at delivery depending on risk.

It is also important to use condoms during sex, even while pregnant, to help prevent syphilis and other sexually transmitted infections (STIs). Pregnant women with syphilis should be treated and monitored appropriately, and their sexual partners should also receive proper care to help prevent reinfection after treatment.