Almost half of all sexually transmitted infections (STIs) in the United States occur in adolescents and young adults, with syphilis cases showing a 74% increase compared to 2017.
How Syphilis Spreads
Syphilis is usually transmitted via sexual contact with an open lesion during the primary or secondary stages of the illness or vertically from mother to child (congenital syphilis). High-risk groups include men who have sex with men, those with multiple sexual partners, and individuals with HIV.
Stages and Symptoms
Syphilis, known as the "great imitator", has three stages:
- Primary Syphilis: Typically presents as a painless genital ulcer at the point of contact, often unnoticed, that heals within 3–6 weeks.
- Secondary Syphilis: Occurs weeks to months after infection, with symptoms such as fever, headache, malaise, anorexia, lymphadenopathy, joint pain, or a maculopapular rash on the palms and soles. This stage can recur for years if untreated.
- Tertiary Syphilis: The final stage, occurring decades after the initial infection, is rare in children. It is marked by the presence of gummas (granulomatous lesions), damage to target organs, syphilitic aortitis, tabes dorsalis, and paresis of the central nervous system.
At any stage, patients can develop neurosyphilis, with neurological symptoms such as vision changes, seizures, neuropathies, or altered mental state.
Diagnosis
Diagnosis involves both physical examination and laboratory testing.
- Physical Exam: A thorough examination, especially of the genitals, skin, lymphatic system, and neurological system, is crucial.
- Testing:
- Non-treponemal tests (RPR and VDRL) are sensitive but not specific and are usually the first choice. False positives can occur with connective tissue disorders or other infections, and false negatives can occur in early primary syphilis or latent infection.
- Treponemal tests (FTA-ABS) confirm the diagnosis by detecting antibodies specifically against treponemal proteins.
- Further Tests: Patients with neurological symptoms should have an eye exam and a cerebrospinal fluid (CSF) test. Testing for other STIs is also recommended.
Treatment and Prognosis
Early treatment is vital, especially for neurosyphilis, to prevent further neurological damage.
- Primary or Secondary Syphilis: A single dose of penicillin G benzathine is usually sufficient. Doxycycline or tetracycline may be used for penicillin-allergic patients.
- Neurosyphilis, Tertiary Syphilis, or Pregnant Patients: Penicillin G is the recommended antibiotic.
- Management of Syphilis During Penicillin Shortages: Consider the stage of the infection and consider an alternative treatment (doxycycline) for non-pregnant patients.
Patients should be counselled about the Jarisch-Herxheimer reaction, which can occur within 24 hours of starting antibiotics. Follow-up includes repeat RPR tests, and for neurosyphilis, repeat CSF samples. The prognosis is excellent with appropriate treatment in primary and secondary syphilis.
Congenital Syphilis
Congenital syphilis, resulting from vertical transmission, has increased tenfold in the last decade.
- Prevention: Prenatal screening is vital, with a 98% efficacy in preventing congenital syphilis if maternal syphilis is adequately treated. Screening should occur early in pregnancy and at 28 weeks, as well as at delivery in high-incidence areas.
- Diagnosis: Neonates at risk should undergo non-treponemal testing. A diagnosis requires an RPR titre four times greater than the maternal titre or abnormal physical findings.
- Symptoms: Most infants are asymptomatic at birth, but symptoms can develop within the first three months, including hepatomegaly, jaundice, runny nose, maculopapular rash, and lymphadenopathy. Late-stage congenital syphilis can manifest with facial deformities, Hutchinson teeth, intellectual disability, and neurological issues.
- Treatment: Early antibiotic treatment is usually curative, but delayed treatment can lead to permanent symptoms.
Recommendations
The U.S. Preventive Services Task Force recommends universal syphilis testing for sexually active adults and adolescents at increased risk. Health professionals are required to report diagnoses to local health departments. Doxycycline can be used as post-exposure prophylaxis against bacterial STIs, including syphilis, if taken within 72 hours of unprotected sex.
