Syphilis, called giang mai in Vietnamese, is a bacterial sexually transmitted infection that can be cured with appropriate antibiotics. It can also remain unnoticed for a long time. A sore may disappear and a rash may fade without the infection being eliminated, so improvement in appearance is not a reliable sign that treatment is unnecessary.
The most useful steps are to recognize possible exposure, obtain the right tests, complete treatment matched to the stage and return for follow-up. Partners may need assessment even if they feel well. Pregnancy, eye symptoms, hearing changes and neurological symptoms require particular attention because they can change the urgency and type of care. This guide explains these distinctions without relying on a photograph to make a diagnosis.
How syphilis is transmitted
Syphilis is caused by Treponema pallidum. Sexual transmission usually occurs through direct contact with an infectious lesion during vaginal, anal or oral sex. Lesions may be on the genitals, anus, rectum, lips or inside the mouth, and some are difficult to see. A person may therefore be unaware that an exposure has occurred.
An infected pregnant person can pass the infection to the fetus. Syphilis is not spread by ordinary contact with toilet seats, shared eating utensils or casual daily interaction. Condoms reduce sexual transmission risk when they cover the infectious area, but sores outside the covered skin can still transmit infection. The protection is therefore useful but incomplete, and a suspicious sore should lead to assessment rather than simply being covered and ignored.
Primary syphilis: the first sore
The first recognized sign may be a chancre, often described as a firm, painless sore at the entry site. There can be more than one, and real presentations are not always textbook examples. A lesion in the mouth, rectum or vagina may go unnoticed. Pain or the absence of a visible ulcer does not reliably rule syphilis out.
The sore can heal without treatment, but bacteria may remain in the body. Do not interpret healing as proof that a cream or home remedy cured the infection. If a genital or oral sore appears after possible sexual exposure, seek an examination and testing. Other causes, including herpes and noninfectious ulcers, may need consideration. Starting random antibiotics before assessment can complicate the picture and may not provide the treatment syphilis requires.
Secondary syphilis: symptoms beyond one site
Secondary syphilis can produce a rash, including on the palms or soles, as well as swollen lymph nodes, fever, sore throat, patchy hair loss or lesions on moist skin and mucosal surfaces. The rash may be subtle and may not itch. No single symptom is present in every case, and several other illnesses can look similar.
Symptoms can disappear even without effective treatment. This is another reason to use testing and clinical assessment rather than waiting to see whether the skin clears. Tell the clinician about a previous sore even if it has healed. A sequence of symptoms separated by weeks can be relevant. Photographs of earlier lesions may help describe the history, but a normal-looking examination today does not exclude an infection acquired earlier.
Latent and late disease
Latent syphilis means tests show infection without current signs of the primary, secondary or tertiary stages. The person may feel entirely well. Clinicians use earlier results, symptoms and exposure history to estimate whether infection is recent or of longer or unknown duration. The date of the first positive test is not necessarily the date the infection began.
Untreated infection can sometimes progress to serious late complications affecting organs such as the heart, blood vessels or nervous system. Not everyone develops these complications, but their possibility is a reason to treat asymptomatic infection. Treatment can prevent further damage, although it may not reverse damage already established. A high or low blood-test number alone cannot reliably determine the stage or justify selecting a shorter course.
Brain, eye and ear involvement
Syphilis can affect the nervous system, eyes or ears at different stages, not only after many years. New blurred vision, eye pain, hearing loss, ringing in the ears, severe headache, weakness, sensory changes or confusion should be reported promptly. Sudden neurological symptoms require emergency assessment regardless of whether syphilis has already been diagnosed.
Eye or hearing involvement may need urgent specialist care because delayed treatment can leave permanent impairment. A clinician may arrange an eye or ear examination and, in selected neurological situations, a lumbar puncture to examine cerebrospinal fluid. A spinal-fluid test is not automatically required for every person with syphilis. The symptom pattern guides investigation, and treatment for these complications differs from routine treatment of uncomplicated early infection.
Understanding the blood tests
Diagnosis usually involves two different categories of blood tests. Treponemal tests look for antibodies associated with the organism. Nontreponemal tests, such as RPR or VDRL, provide information useful in assessing activity and following the response to treatment. Laboratories may start with either category, then use additional testing to clarify the result.
A positive screening result is not always a complete diagnosis by itself. Previous treatment, early infection, false-positive results and disagreement between tests can require interpretation. Treponemal tests often remain positive for many years or for life after successful treatment. That persistent result does not automatically mean that treatment failed. Bring previous results and treatment dates if available, because they can prevent confusion between a new infection and a record of an old treated one.
Timing after an exposure
Very early infection may not yet produce a positive blood test. If a sore is present or a recent partner has been diagnosed, a clinician may recommend repeat testing, direct testing of a lesion where available or treatment based on the exposure. A negative test immediately after sex should not be treated as a guarantee that nothing was transmitted.
The appropriate repeat-testing schedule depends on when exposure occurred, symptoms and the tests used. Do not delay assessment until a particular number of weeks has passed if you have a lesion, are pregnant or have eye, ear or neurological symptoms. Partner-management recommendations can include treatment before a test becomes positive in some situations. That decision is based on clinical risk, not a reason to obtain antibiotics without evaluation.
Treatment depends on stage and circumstances
Penicillin is the main treatment for syphilis, but the preparation and schedule matter. Uncomplicated early infection may be treated with a single injection of long-acting benzathine penicillin, while late latent infection or infection of unknown duration generally needs a longer injection schedule. Neurosyphilis, ocular syphilis and otosyphilis require a different regimen, often involving intravenous treatment.
These are clinical treatment categories, not instructions to buy a penicillin product and administer it yourself. Similar drug names do not make formulations interchangeable. Pregnancy, allergy history and complications affect the plan. In selected nonpregnant people, an alternative antibiotic may be considered with careful follow-up. Do not substitute leftover amoxicillin or stop after symptoms disappear. If a scheduled dose is missed, contact the treating service because the next step can depend on the delay and pregnancy status.
Reactions after starting treatment
Some people develop fever, chills, headache or muscle aches within the first day after treatment, called a Jarisch–Herxheimer reaction. It reflects the body's response to treatment of the infection and is not the same as penicillin allergy. The treating clinician can explain what symptoms to expect and what supportive measures are appropriate.
Do not assume every new symptom is this reaction. Difficulty breathing, facial or throat swelling, collapse or other signs of a severe allergic reaction require emergency care. Pregnancy makes fever, contractions or reduced fetal movement particularly important to report urgently. Concern about a possible reaction should not delay necessary syphilis treatment; it should lead to a clear plan for monitoring and getting help if symptoms develop.
Follow-up shows whether the response is appropriate
Follow-up combines clinical review with repeat quantitative nontreponemal tests. The clinician compares the titer with the value at treatment, preferably using a consistent test method and laboratory. The expected pattern and timing vary by stage, previous infection and other factors. A positive result after treatment is not interpreted simply as “still infected” without looking at which test was used and how the numbers changed.
A substantial sustained rise can suggest reinfection or treatment failure and needs reassessment. Some people retain a stable low titer despite adequate treatment, sometimes described as a serofast state. This does not automatically call for repeated antibiotics, but it requires professional interpretation. Keep follow-up appointments even when you feel well, and report new exposures or recurrent symptoms so the clinician can distinguish a new problem from the expected course.
Partners and returning to sex
Recent sexual partners may need confidential notification, testing and sometimes treatment. Which partners need assessment depends on the stage and exposure dates. A partner without symptoms may still have infection. Treating only one person while an exposed partner remains unassessed can lead to reinfection, because successful treatment does not create lasting immunity.
Follow the treating clinician's advice about avoiding sexual contact until treatment and partner management are complete and any lesions have healed. Do not rely on a healed sore alone or assume a condom removes all risk during active infection. Notification can be uncomfortable, but it is a practical step in protecting both people. A sexual-health service may help explain or support confidential partner notification where such services are available.
Pregnancy and congenital syphilis
Syphilis during pregnancy can cause miscarriage, stillbirth, premature birth or serious infection in the baby. A baby may initially look well and still need assessment. Testing early in pregnancy and repeat testing when indicated are important even when there are no symptoms. A prior negative result does not exclude infection acquired later in pregnancy.
Penicillin is the established treatment for preventing transmission to the fetus and treating maternal infection. A reported penicillin allergy requires specialist evaluation; desensitization may be needed rather than replacing treatment with an unproven alternative. Do not postpone care because you feel healthy or because delivery is approaching. The maternity and treating teams need the test results, treatment dates and information about possible reinfection to plan care for both parent and baby.
Other STI tests and future prevention
A syphilis diagnosis is a reason to discuss HIV testing and other STI testing suited to the exposure sites and circumstances. An oral or rectal exposure may require consideration beyond a urine sample. For someone at continuing HIV risk, PrEP may be relevant, but HIV prevention medication does not treat syphilis or replace syphilis testing.
Use condoms consistently, discuss testing with partners and seek assessment for unexplained sores or rashes. There is no routine syphilis vaccine that replaces these measures. Antibiotic prevention strategies used for selected populations require an individualized clinical discussion and should not become unsupervised repeated antibiotic use. The goal is a prevention plan that fits actual exposure, rather than assuming one negative test offers permanent protection.
When to act and what to remember
Arrange testing after a partner's diagnosis, a possible exposure with symptoms or a new unexplained genital, anal or oral lesion. Seek urgent care for visual changes, hearing loss, severe neurological symptoms or concerns during pregnancy. A rash disappearing on its own is not a reason to cancel testing, and a persistent positive treponemal test after documented treatment is not proof of treatment failure.
Syphilis care is a sequence: establish the diagnosis, determine the stage, give the correct treatment, address partners and document the follow-up response. Each step answers a different question. In Vietnam, as elsewhere, prompt assessment and completion of that sequence are more useful than self-treatment based on a symptom photograph. The infection is curable, and earlier appropriate care reduces the chance of preventable complications.
Frequently Asked Questions
Can I use this article to diagnose or treat myself?
No. It provides general information and practical planning points. A clinician or pharmacist should assess individual symptoms, diagnoses, medicines and treatment decisions.
What information should I verify before acting?
Verify details that can change, such as appointment schedules, fees, medicine stock, service availability and local instructions, using the current official source.
What should I bring to a medical appointment?
Bring identification when required, a medication and allergy list, relevant previous records and a short timeline of symptoms. For specialist care, include prior imaging or test reports when available.
When should I seek urgent medical help?
Seek urgent care for severe or rapidly worsening symptoms, breathing difficulty, fainting, major bleeding, new neurological symptoms or another situation that feels immediately dangerous.
Sources
Writer
Tan Nguyen
Medical writer for Vietnam Clinic. MD, Vietnam National University Ho Chi Minh City.
