Syphilis complicating pregnancy, second trimester in Chile: Symptoms, Causes & Treatment | aihealz
ICD variantSyphilis complicating pregnancy, second trimester is a specific ICD-10 coded subtype of Syphilis. The clinical content below covers Syphilis in general.
ObstetricsmoderateICD-10 · O98.112
Syphilis complicating pregnancy, second trimester.Care & specialists in Chile
In Chile, syphilis complicating pregnancy, second trimester is managed by obstetricss. Syphilis is a sexually transmitted bacterial infection caused by the spirochete Treponema pallidum, which spreads through direct contact with infectious sores and through the placenta from mother to fetus. United States cases reached 207,255 in 2022 — the highest count since 1950 and a 80% rise over five years — with primary, secondary, and early latent cases now reported in every age band from 15 to 65.
Syphilis (ICD-10: A50-A53) is a chronic systemic infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum, transmitted primarily through sexual contact with an infectious lesion and vertically from a pregnant person to the fetus. The organism is a slow-replicating, microaerophilic spirochete that cannot be grown on standard culture media, which is why diagnosis relies on dark-field microscopy, serology, or molecular methods rather than culture. After inoculation, treponemes disseminate hematogenously within hours, producing a sequence of clinical stages: primary (painless chancre at the site of inoculation, 10-90 days after exposure), secondary (mucocutaneous rash, lymphadenopathy, and systemic symptoms 4-10 weeks later), early and late latent (asymptomatic but seropositive), and tertiary (cardiovascular syphilis, gummatous lesions, neurosyphilis) developing in 25-40% of untreated patients over 10-30 years. Neurologic involvement can occur at any stage, and ocular and otic syphilis are increasingly recognized presentations.
key facts
Prevalence
207,255 US cases (CDC 2022); ~8 million new global infections annually (WHO 2020)
Demographics
Men (especially men who have sex with men) account for 80% of US primary and secondary cases; women aged 20-34 are the fastest-rising group
Avg. age
Median age at diagnosis 30-39; congenital cases peak in newborns of women aged 20-29
Global cases
~36 million prevalent infections worldwide (WHO 2020); 700,000+ cases of congenital syphilis annually
Specialist
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How you might notice it
The key symptoms of Syphilis complicating pregnancy, second trimester are: A single firm, painless, indurated genital, anal, or oral ulcer (chancre) with raised edges and a clean base, appearing 10-90 days after exposure and persisting 3-6 weeks before healing on its own., Painless regional lymphadenopathy near the chancre, typically inguinal nodes that are firm, mobile, and non-tender., A diffuse non-itchy maculopapular or papulosquamous rash 4-10 weeks later, characteristically involving the palms and soles and sparing the face in most adults., Mucous patches — shallow, painless gray-white erosions on the oral or genital mucosa during secondary syphilis, highly infectious on contact., Condyloma lata — moist, flat, pink-gray wart-like papules in skin folds (perianal, vulvar, axillary) that are teeming with treponemes and highly contagious., Patchy, moth-eaten alopecia of the scalp, eyebrows, and beard during the secondary stage, with hair regrowth after treatment., Generalized lymphadenopathy, low-grade fever, headache, sore throat, malaise, and weight loss accompanying the secondary rash..
01A single firm, painless, indurated genital, anal, or oral ulcer (chancre) with raised edges and a clean base, appearing 10-90 days after exposure and persisting 3-6 weeks before healing on its own.
02Painless regional lymphadenopathy near the chancre, typically inguinal nodes that are firm, mobile, and non-tender.
03A diffuse non-itchy maculopapular or papulosquamous rash 4-10 weeks later, characteristically involving the palms and soles and sparing the face in most adults.
04Mucous patches — shallow, painless gray-white erosions on the oral or genital mucosa during secondary syphilis, highly infectious on contact.
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How it’s diagnosed
diagnosis
Diagnosis combines clinical recognition with serologic testing, since T. pallidum cannot be grown in routine culture. The standard workflow uses two complementary blood tests: a non-treponemal test (RPR or VDRL) that quantifies disease activity through measurable titers, and a treponemal test (FTA-ABS, TP-PA, or chemiluminescent immunoassay) that confirms exposure but remains positive for life. Many US labs now run a reverse algorithm — automated treponemal screening followed by reflex RPR — which catches early infection and late latent disease that non-treponemal tests can miss. Discordant results require a second treponemal assay (TP-PA) to resolve. Direct visualization of treponemes by dark-field microscopy or PCR of swabbed lesion exudate confirms primary or secondary disease when a chancre or mucous patch is accessible. Any reactive serology in a person with new neurologic, ocular, or otic symptoms warrants lumbar puncture and ophthalmologic or audiologic examination. CSF VDRL is the diagnostic test for neurosyphilis; an elevated CSF white cell count and protein in the right clinical context also support the diagnosis. Staging matters because treatment duration differs: a single benzathine penicillin G dose for primary, secondary, and early latent disease, three weekly doses for late latent and tertiary disease without neurologic involvement, and 10-14 days of intravenous aqueous penicillin G for neurosyphilis, ocular, or otic syphilis. The CDC recommends every patient with new syphilis also be tested for HIV, gonorrhea, chlamydia, and hepatitis B and C at the same visit.
Key tests
01
Rapid plasma reagin (RPR) or VDRL — non-treponemal serologyDetects antibody to cardiolipin released by treponeme-damaged cells; the titer quantifies disease activity and tracks response to treatment. A fourfold drop in titer over 6-12 months defines successful treatment.
02
Treponemal test (TP-PA, FTA-ABS, or CIA/EIA)Confirms exposure to T. pallidum. Becomes positive 2-3 weeks before non-treponemal tests and remains positive for life regardless of treatment.
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Treatment & cost
medical treatments
✓Benzathine penicillin G 2.4 million units IM, single dose
✓Benzathine penicillin G 2.4 million units IM weekly × 3 doses
✓Aqueous crystalline penicillin G 18-24 million units/day IV × 10-14 days
✓Procaine penicillin G 2.4 million units IM daily + probenecid 500 mg PO four times daily × 10-14 days
surgical options
Aortic root replacement or repair (cardiovascular syphilis)Operative mortality 3-8% in centers experienced with luetic aortitis; outcomes comparable to non-luetic aortic root replacement.
Surgical drainage of gummatous abscessconsult specialist
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Causes & risk factors
known causes
Sexual transmission of Treponema pallidum
Direct mucosal or skin contact with an infectious chancre, mucous patch, or condyloma lata during vaginal, anal, or oral sex. Per-act transmission risk from an untreated partner with a chancre is approximately 30%. Treponemes traverse intact mucosa or microabrasions within minutes.
Vertical (transplacental) transmission
An untreated pregnant person can pass T. pallidum to the fetus from approximately week 14 of pregnancy onward, with risk approaching 80% in early maternal syphilis. Outcomes include stillbirth, preterm birth, neonatal death, and congenital syphilis.
Blood-borne transmission
Rare in countries with screened blood supplies, but documented in shared injection drug use and through transfusion of contaminated blood, especially in resource-limited settings where pre-donation serologic screening is inconsistent.
HIV co-infection biology
HIV does not cause syphilis but markedly accelerates its course. Co-infected patients have higher treponemal loads, more aggressive neurologic involvement, more frequent serologic relapse after treatment, and slower decline of RPR titers, which is why ID guidelines recommend lower thresholds for lumbar puncture in this group.
Inadequate prenatal screening and treatment
Congenital syphilis is almost entirely preventable with three RPR tests in pregnancy (first trimester, third trimester, delivery) and timely benzathine penicillin G when positive. Cases reflect missed screening, late prenatal care, or inadequate maternal treatment — over 80% of US 2022 congenital cases had at least one preventable system failure.
risk factors
Unprotected sex with new or multiple partnersmodifiable
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Living with it
01Use latex or polyurethane condoms consistently and correctly during vaginal, anal, and oral sex — reduces but does not eliminate risk
02Screen for syphilis every 3-6 months if you are a man who has sex with men, are living with HIV, or have multiple sexual partners
03Notify recent sexual partners (within 90 days) of any positive diagnosis so they can be treated presumptively
04Complete the universal pregnancy screening schedule — first trimester, third trimester, and at delivery — and treat any positive result with benzathine penicillin G well before delivery
05Discuss doxycycline post-exposure prophylaxis (doxy-PEP) with a sexual health clinician if you are an MSM or transgender woman at high STI risk — reduces syphilis incidence by ~60% in trials
recommended foods
•Standard balanced nutrition supports immune recovery during treatment
•Adequate hydration during the Jarisch-Herxheimer reaction (first 24 hours after first penicillin dose)
•Folate-rich foods if pregnant and being treated, alongside standard prenatal vitamins
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When to seek help
why see an obstetrics
An infectious disease physician or sexual health specialist should be involved in any syphilis case with neurologic, ocular, or otic symptoms; in HIV co-infection; in pregnancy with confirmed allergy to penicillin; in suspected serologic non-response or reinfection; and in tertiary disease. Primary care and sexual health clinics manage most uncomplicated early infections according to CDC algorithms.
Primary syphilisA single painless, indurated ulcer (chancre) at the site of inoculation — genitals, anus, lips, or oral cavity — appearing 10-90 days after exposure and healing spontaneously in 3-6 weeks even without treatment.
Secondary syphilisA systemic phase 4-10 weeks after chancre onset, marked by a non-itchy maculopapular rash that classically involves palms and soles, generalized lymphadenopathy, mucous patches, condyloma lata, fever, and patchy alopecia.
Latent syphilisAsymptomatic seropositive infection. Early latent (within one year of infection) is potentially infectious; late latent (over one year) is not sexually transmissible but still treatable to prevent progression.
Tertiary syphilisLate complications appearing 10-30 years after untreated infection: gummatous lesions of skin, bone, and viscera; cardiovascular syphilis with thoracic aortic aneurysm and aortic regurgitation; tabes dorsalis and general paresis.
Neurosyphilis, ocular and otic syphilisCNS, eye, or inner ear involvement that may occur at any stage. Presentations include meningitis, stroke, dementia, optic neuritis, uveitis, hearing loss, and tinnitus. Lumbar puncture and ophthalmologic exam guide management.
Congenital syphilisTransplacental infection of a fetus by an untreated pregnant person. Causes stillbirth in up to 40% of cases and a wide range of neonatal and late childhood manifestations covered on the dedicated congenital syphilis page.
Living with Syphilis complicating pregnancy, second trimester
Timeline
Primary chancre heals within 3-6 weeks of treatment, often faster. Secondary rash and mucosal lesions usually clear within 1-2 weeks. RPR titer should drop fourfold by 6 months and at least eightfold by 12 months. CSF normalization in neurosyphilis takes 6-12 months. Visible aortic or neurologic damage from tertiary disease does not reverse but progression halts. Patients are considered non-infectious 7 days after benzathine penicillin G administration.
Lifestyle
01Avoid all sexual contact until 7 days after completing treatment and until any visible lesions have fully healed
02Recheck RPR titer at 6 and 12 months (24 months if late latent or HIV co-infected) to confirm serologic cure
03Receive HIV pre-exposure prophylaxis (PrEP) if you remain at ongoing risk after treatment
04Disclose syphilis history to future obstetric care providers — even successfully treated past infection alters prenatal screening cadence
05Avoid pregnancy until 30 days after completing late latent treatment if you have late or unknown-duration disease
06Address substance use and mental health if these have driven risk behavior — treat the underlying driver to prevent reinfection
Daily management
01Attend all serologic follow-up appointments at 6 and 12 months — and 24 months if HIV co-infected or late latent
Choosing a doctor
Look for a clinician comfortable with the CDC 2021 STI Treatment Guidelines, with access to benzathine penicillin G, and with established referral pathways to ophthalmology, audiology, and neurology. Sexual health clinics and ID departments at academic centers usually offer rapid testing, partner notification support, and HIV/STI bundle screening. Continuity matters because serologic follow-up extends over 12-24 months.
Patient support resources
CDC — Syphilis Fact Sheet →Authoritative US patient education with current statistics and treatment summaries.
WHO — Syphilis →Global STI surveillance and prevention resources.
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Frequently asked
Can syphilis be cured?▾▴
Yes. A single intramuscular injection of benzathine penicillin G cures over 95% of patients with primary, secondary, or early latent syphilis. Late and tertiary stages need three weekly doses; neurosyphilis needs 10-14 days of intravenous penicillin.
What is the first sign of syphilis?▾▴
The first sign is a single firm, painless ulcer called a chancre at the site where the bacterium entered — usually the genitals, anus, mouth, or lips. It appears 10-90 days after exposure and heals on its own in 3-6 weeks, but the infection persists and progresses if untreated.
How is syphilis spread?▾▴
Syphilis spreads through direct contact with an infectious chancre or mucosal lesion during vaginal, anal, or oral sex. It can also pass from a pregnant person to the fetus through the placenta. It does not spread through toilet seats, swimming pools, shared utensils, or casual contact.
How long does syphilis take to show up on a test?▾▴
Non-treponemal blood tests (RPR, VDRL) usually turn positive 3-6 weeks after exposure. Treponemal tests turn positive slightly earlier (2-3 weeks). After very recent exposure, a clinician may retest in 3-6 weeks to confirm.
What are the stages of syphilis?▾▴
Syphilis has four stages: primary (painless chancre), secondary (rash and flu-like symptoms 4-10 weeks later), latent (asymptomatic but seropositive), and tertiary (cardiovascular, neurologic, or gummatous disease 10-30 years later).
Is syphilis serious?▾▴
Untreated syphilis is serious. About one in three untreated patients develops tertiary complications — aortic aneurysm, stroke, dementia, blindness, or deafness — over 10-30 years. In pregnancy it causes stillbirth or neonatal death in up to 40% of cases. Early treatment prevents these outcomes.
Can you get syphilis more than once?▾▴
Yes. Successful treatment does not produce lasting immunity, so reinfection is common in patients with ongoing exposure. Reported reinfection rates are 10-20% within 2 years in high-risk populations. Regular screening every 3-6 months is recommended for those at ongoing risk.
What is the rash of secondary syphilis like?▾▴
The classic secondary syphilis rash is a non-itchy, symmetric, copper-red maculopapular eruption that involves the palms and soles. It appears 4-10 weeks after the chancre, persists 2-6 weeks, and may accompany mucous patches, lymphadenopathy, and patchy hair loss.
Why are syphilis rates rising?▾▴
US cases rose 80% from 2018 to 2022, reaching 207,255 — the highest since 1950. Drivers include declining condom use, methamphetamine and opioid use, reduced public health funding, dating app-mediated partner change, and missed prenatal screening. The rise affects every demographic and geography.
Does penicillin cure syphilis at every stage?▾▴
Penicillin is effective at every stage, but dose and route differ. A single IM shot cures early disease in over 95%. Late latent needs three weekly shots. Neurosyphilis and ocular or otic disease need 10-14 days of IV penicillin. No resistance has emerged in T. pallidum.
What is the Jarisch-Herxheimer reaction?▾▴
A short febrile inflammatory response within 2-12 hours of the first penicillin dose, especially in secondary syphilis. About 50% of patients get fever, chills, headache, and myalgia for up to 24 hours. It is self-limited; treat with rest, fluids, and acetaminophen.
Can I have sex during syphilis treatment?▾▴
No. Avoid sex for at least 7 days after benzathine penicillin G, and until any visible sores have fully healed. Partners within the prior 90 days should be tested and presumptively treated. Follow-up RPR at 6 and 12 months confirms cure.
Can syphilis affect the brain?▾▴
Yes. Neurosyphilis can develop at any stage and includes meningitis, stroke, dementia (general paresis), and tabes dorsalis. Any new neurologic, eye, or ear symptom in a patient with positive syphilis serology warrants lumbar puncture and urgent IV treatment.
How does syphilis affect pregnancy?▾▴
Untreated syphilis in pregnancy causes stillbirth, neonatal death, or congenital syphilis in up to 80% of pregnancy-acquired cases. Screening at the first prenatal visit, third trimester, and delivery with prompt benzathine penicillin G cuts risk to under 2%.
Is syphilis testing accurate?▾▴
Combined non-treponemal (RPR/VDRL) and treponemal (TP-PA/FTA-ABS) testing is highly accurate. Sensitivity exceeds 95% in secondary and latent disease but is 75-85% in very early primary disease, when retesting in 3-6 weeks may be needed.
Will my syphilis test always be positive after treatment?▾▴
Treponemal tests (TP-PA, FTA-ABS, CIA) remain positive for life regardless of cure. Non-treponemal tests (RPR, VDRL) drop fourfold or become non-reactive within 12 months of successful treatment, and their titer is used to confirm cure or detect reinfection.
Can syphilis be prevented with doxycycline?▾▴
Doxycycline post-exposure prophylaxis (doxy-PEP), 200 mg within 72 hours of sex, reduces incident syphilis by about 60% in MSM and transgender women per randomized trials. CDC 2024 guidance recommends discussion for these high-risk groups; not for cisgender women.
How much does syphilis treatment cost?▾▴
Benzathine penicillin G costs USD 30-80 per dose in the US generic market and is heavily subsidized in public sexual health clinics. Most US health departments offer free testing and treatment. Generic doxycycline costs under USD 20 for 14 days.
What if I'm allergic to penicillin?▾▴
Non-pregnant patients can take doxycycline 100 mg twice daily for 14 days (early) or 28 days (late latent). Pregnant patients are always desensitized to penicillin because no alternative reliably prevents congenital syphilis.
Should partners be tested and treated?▾▴
Yes. Sexual contacts within the prior 90 days of a primary, secondary, or early latent diagnosis should be presumptively treated with benzathine penicillin G regardless of test results. Contacts within 90 days to 1 year are tested and treated based on findings.
When should I be screened for syphilis?▾▴
USPSTF recommends screening any sexually active person at increased risk. MSM and people with HIV should be screened every 3-6 months. All pregnant patients are screened at first prenatal visit, third trimester, and delivery.
05Condyloma lata — moist, flat, pink-gray wart-like papules in skin folds (perianal, vulvar, axillary) that are teeming with treponemes and highly contagious.
06Patchy, moth-eaten alopecia of the scalp, eyebrows, and beard during the secondary stage, with hair regrowth after treatment.
07Generalized lymphadenopathy, low-grade fever, headache, sore throat, malaise, and weight loss accompanying the secondary rash.
08Long asymptomatic periods (latent syphilis) lasting months to decades, during which only serologic testing detects ongoing infection.
09Late neurologic features in tertiary disease: progressive memory loss, personality change, ataxia, lightning pains in the legs, urinary incontinence, or Argyll Robertson pupils that accommodate but do not react to light.
10Painful destructive granulomatous lesions (gummas) on skin, bones, or internal organs in the tertiary stage, sometimes mistaken for malignancy.
early warning signs
•Any new painless genital, anal, or oral ulcer in someone sexually active — even a single self-healing sore warrants testing
•A diffuse symmetric rash on the trunk that involves the palms and soles, particularly in a person with recent unprotected sex
•Unexplained patchy hair loss combined with mucosal sores or rash
•A new sexual contact known or suspected to have syphilis (notify and test even if asymptomatic)
● emergency signs
•Sudden vision loss, double vision, or eye pain in a person with known or suspected syphilis — ocular syphilis requires same-day ophthalmology and intravenous treatment
•Acute stroke, seizure, or confusion in a sexually active adult — neurosyphilis is now seen in young patients with HIV co-infection
•Severe headache, neck stiffness, and fever — possible syphilitic meningitis at any stage
•Sudden sensorineural hearing loss or vertigo with positive syphilis serology — otic syphilis demands urgent treatment
•Chest pain or new diastolic murmur in a patient with untreated late syphilis — possible aortic aneurysm or aortic regurgitation
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Dark-field microscopy of lesion exudateDirect visualization of motile spirochetes from a chancre, mucous patch, or condyloma lata. Confirms diagnosis instantly when positive and is especially useful in the window before serology turns positive.
04
Treponemal PCR from lesion swabDetects treponemal DNA directly. Sensitivity 75-95% from primary chancres; useful when dark-field microscopy is unavailable or the patient has already started antibiotics.
05
Lumbar puncture with CSF analysisRequired when neurologic, ocular, or otic symptoms are present, or when serologic non-response occurs. CSF VDRL is highly specific but only 30-70% sensitive; CSF white cells, protein, and treponemal index aid diagnosis.
06
Ophthalmologic and audiologic examinationDetects ocular syphilis (uveitis, optic neuritis, retinal vasculitis) and otic syphilis (sensorineural hearing loss, vertigo). Required in any patient with eye or ear symptoms and reactive serology.
07
HIV, gonorrhea, chlamydia, hepatitis B and C screeningCo-infection rates are high; bundled testing is recommended at every new syphilis diagnosis (CDC 2021).
Outlook
With timely benzathine penicillin G, the prognosis for primary, secondary, and early latent syphilis is excellent — over 95% of immunocompetent patients achieve serologic cure within 12 months and have no long-term sequelae. Late latent disease responds in 70-90% of cases, though existing organ damage (aortic aneurysm, neurologic deficits, optic atrophy) does not reverse. Neurosyphilis treated promptly shows clinical improvement in 70-80% of patients, with CSF parameters normalizing over 6-12 months. Reinfection is common in high-risk populations, with reported rates of 10-20% within 2 years of initial cure. Untreated, roughly 25% of infections progress to late latent or tertiary disease over 10-30 years, and roughly one-third of untreated patients develop devastating cardiovascular, neurologic, or gummatous complications. The historic Oslo (1891-1951) and Tuskegee cohort data — though ethically indefensible in their conduct — established that fewer than 10% of untreated patients die directly of syphilis, but many more sustain irreversible end-organ damage. Pregnancy outcomes are dramatic: untreated early maternal syphilis causes stillbirth or neonatal death in up to 40% of cases, while timely treatment reduces this to under 2%.
The strongest modifiable risk factor. Consistent condom use reduces but does not eliminate risk, since chancres can occur on areas not covered by a condom (scrotum, base of penis, perianal skin).
Men who have sex with men (MSM)non-modifiable
MSM account for roughly 47% of US primary and secondary syphilis cases. Higher background prevalence and condomless receptive anal sex are the main drivers. Routine screening every 3-6 months is recommended.
HIV infectionnon-modifiable
HIV and syphilis share transmission routes and biology. Up to 40% of US MSM with syphilis are HIV-positive. CDC recommends syphilis testing at every HIV care visit.
Pregnancy without adequate prenatal screeningmodifiable
Pregnant individuals not screened in the first trimester, third trimester, and at delivery — or screened but not treated — drive nearly all congenital syphilis. USPSTF and CDC strongly recommend universal triple-test screening.
Methamphetamine, heroin, and cocaine usemodifiable
Substance use is now linked to over 40% of US heterosexual syphilis cases (CDC 2022). Drug-related disinhibition, transactional sex, and reduced engagement with healthcare are the mechanisms.
Sex work or transactional sexmodifiable
High partner numbers and inconsistent condom use raise risk substantially. Outreach screening programs reach populations less likely to attend clinic-based care.
Residence in or travel to high-prevalence regionsenvironmental
Sub-Saharan Africa, parts of Latin America, and several US states (Arizona, New Mexico, Mississippi) have prevalence 3-10× the national average. Local epidemiology informs screening intensity.
Age 15-34non-modifiable
65% of US primary and secondary syphilis cases occur in this band. Sexual debut, partner change rate, and inconsistent contraception/STI prevention drive incidence.
foods to avoid
•Alcohol during the first week of treatment if doxycycline is the chosen regimen — can worsen GI side effects
•Probiotic supplements within 2 hours of doxycycline — interferes with absorption
•Iron, calcium, or antacid supplements within 2 hours of doxycycline — chelation reduces drug levels
07Increased HIV acquisition and transmission risk — syphilitic ulcers facilitate HIV exchange by 2-5 fold
02Take doxycycline (if prescribed) on a full stomach with a large glass of water, and remain upright for 30 minutes to prevent esophagitis
03Use barrier protection during all sexual contact until 7 days after treatment completion
04Inform any new healthcare providers of past syphilis diagnosis — treponemal tests remain positive for life and may confuse future screens
05Notify ongoing partners of any new test result and encourage them to be tested
Exercise
No specific restrictions apply for early syphilis once treatment has started. After the first penicillin injection, rest for the day in case of Jarisch-Herxheimer reaction. Resume normal activity once acute symptoms resolve.