Syphilis

Syphilis (Treponema pallidum Infection)

Medical content reviewed and approved by Dr. GP Yadav, MD, Dermatology Specialist; STI/STD Expert

Definition

Syphilis is a systemic sexually transmitted infection caused by the spirochete bacterium Treponema pallidum. It progresses through primary, secondary, latent, and tertiary stages with diverse clinical manifestations involving the skin, mucous membranes, cardiovascular, and central nervous system.

Symptoms of Syphilis

Syphilis presents in distinct stages. Primary syphilis features a painless chancre at the infection site appearing 9-90 days after exposure, typically resolving spontaneously within 3-6 weeks. Secondary syphilis develops 2-8 weeks after the chancre, with a generalized maculopapular rash involving the trunk, palms, and soles, along with condyloma lata, mucous patches, lymphadenopathy, fever, and malaise. Latent syphilis is asymptomatic but serologically positive. Tertiary syphilis (years later) involves gummatous lesions, cardiovascular syphilis (aortitis), and neurosyphilis (general paresis, tabes dorsalis).

Common Symptoms:

Painless chancre at inoculation site (primary syphilis)
Generalized maculopapular rash on trunk and extremities (secondary)
Condyloma lata and mucous patches (secondary)
Asymptomatic latent period
Gummatous lesions, cardiovascular and neurological involvement (tertiary)

Clinical Images

Primary syphilis chancre on penis showing painless indurated ulcer with clean base and rolled edges characteristic of Treponema pallidum infection — Primary syphilis chancre on the penis demonstrating the classic painless, indurated ulcer with a clean base and rolled edges, the hallmark of primary syphilis.
Image provided by Dr. GP Yadav

Secondary syphilis maculopapular rash on trunk showing generalized copper-colored papulosquamous lesions with characteristic distribution pattern — Secondary syphilis presenting as a generalized maculopapular rash on the trunk with copper-colored papulosquamous lesions in a characteristic distribution.
Image provided by Dr. GP Yadav

Secondary syphilis rash on palms showing characteristic copper-colored papulosquamous lesions pathognomonic for Treponema pallidum dissemination — Secondary syphilis involving the palms with characteristic copper-colored papulosquamous lesions, a pathognomonic finding in secondary syphilis.
Image provided by Dr. GP Yadav

Secondary syphilis rash on soles showing hyperpigmented papulosquamous lesions with desquamation caused by Treponema pallidum dissemination — Secondary syphilis on the soles demonstrating hyperpigmented papulosquamous lesions with desquamation, a characteristic finding of disseminated spirochete infection.
Image provided by Dr. GP Yadav

Condyloma lata in secondary syphilis showing moist flat-topped papular lesions in perianal region highly infectious with abundant Treponema pallidum — Condyloma lata in secondary syphilis demonstrating moist, flat-topped papular lesions in the perianal region, which are highly infectious lesions.
Image provided by Dr. GP Yadav

Syphilitic mucous patches on oral mucosa showing painless silver-gray erosions with surrounding erythema in secondary Treponema pallidum infection — Syphilitic mucous patches on the oral mucosa presenting as painless, silver-gray erosions with a surrounding erythematous halo in secondary syphilis.
Image provided by Dr. GP Yadav

Secondary syphilis papular rash on face showing disseminated copper-colored papules with characteristic distribution and morphology — Secondary syphilis involving the face with disseminated copper-colored papular lesions demonstrating the characteristic morphology of spirochete dissemination.
Image provided by Dr. GP Yadav

Syphilitic alopecia showing moth-eaten pattern of hair loss on scalp caused by Treponema pallidum infection in secondary stage — Syphilitic alopecia demonstrating the characteristic moth-eaten pattern of patchy hair loss on the scalp, a distinctive finding in secondary syphilis.
Image provided by Dr. GP Yadav

Tertiary syphilis gummatous lesion on leg showing destructive nodular ulcerative lesion with punched-out appearance and serpiginous border — Tertiary syphilis gumma on the lower extremity demonstrating a destructive nodular ulcerative lesion with a characteristic punched-out appearance and serpiginous border.
Image provided by Dr. GP Yadav

Primary syphilis chancre on female labia showing painless indurated ulcer with clean base characteristic of early Treponema pallidum infection — Primary syphilis chancre on the female labia demonstrating a painless, indurated ulcer with a clean base, the classic presentation of early syphilis.
Image provided by Dr. GP Yadav

Secondary syphilis annular papular rash on penis showing ring-shaped papulosquamous lesions with central clearing typical of Treponema pallidum infection — Secondary syphilis presenting as annular papular lesions on the penis with ring-shaped morphology and central clearing, a variant presentation of secondary syphilis.
Image provided by Dr. GP Yadav

Syphilitic lymphadenopathy showing enlarged firm non-tender epitrochlear lymph nodes in secondary syphilis caused by Treponema pallidum — Syphilitic lymphadenopathy demonstrating enlarged, firm, non-tender epitrochlear lymph nodes, a common finding in secondary syphilis.
Image provided by Dr. GP Yadav

Congenital syphilis showing rhagades perioral fissures and scarring in infant with Treponema pallidum infection acquired from mother during pregnancy — Congenital syphilis demonstrating rhagades (perioral fissures and scarring) in an infant, a classic stigmata of untreated maternal syphilis during pregnancy.
Image provided by Dr. GP Yadav

Syphilitic leukoderma on neck showing depigmented macular lesions with hyperpigmented borders in secondary Treponema pallidum infection — Syphilitic leukoderma on the neck presenting as depigmented macular lesions with hyperpigmented borders, also known as collar of Venus in secondary syphilis.
Image provided by Dr. GP Yadav

Tertiary syphilis nodular lesion on face showing destructive granulomatous gumma with ulceration and crusting caused by Treponema pallidum — Tertiary syphilis nodular lesion on the face showing a destructive granulomatous gumma with ulceration and crusting, representing late-stage Treponema pallidum infection.
Image provided by Dr. GP Yadav

Secondary syphilis pustular rash showing pustular lesions on erythematous base with crusting characteristic of severe spirochete dissemination — Secondary syphilis presenting as pustular lesions on an erythematous base with crusting, representing a less common but more severe morphological variant.
Image provided by Dr. GP Yadav

Syphilitic onychia and paronychia showing nail plate dystrophy and periungual inflammation caused by Treponema pallidum infection — Syphilitic nail involvement demonstrating onychia and paronychia with nail plate dystrophy and periungual inflammation, an uncommon manifestation of secondary syphilis.
Image provided by Dr. GP Yadav

Primary syphilis chancre on glans penis showing solitary painless indurated ulcer with clean base and raised borders diagnostic of Treponema pallidum — Primary syphilis chancre on the glans penis showing a solitary, painless, indurated ulcer with a clean base and raised, rolled borders, the classic chancre.
Image provided by Dr. GP Yadav

Secondary syphilis generalized lymphadenopathy with multiple enlarged firm non-tender lymph nodes in cervical axillary and inguinal regions — Secondary syphilis with generalized lymphadenopathy showing multiple enlarged, firm, non-tender lymph nodes in the cervical, axillary, and inguinal regions.
Image provided by Dr. GP Yadav

Syphilitic glossitis showing oral mucosal patches and erosion on tongue with depapillation caused by secondary Treponema pallidum infection — Syphilitic glossitis presenting with oral mucosal patches and erosion on the tongue with areas of depapillation, an oral manifestation of secondary syphilis.
Image provided by Dr. GP Yadav

Transmission of Syphilis

Syphilis is transmitted through direct contact with infectious lesions during vaginal, anal, or oral sex. The spirochete penetrates intact mucous membranes or enters through microscopic abrasions in the skin. Vertical transmission occurs at any stage of pregnancy, causing congenital syphilis with potentially fatal fetal outcomes. The risk of transmission from an untreated pregnant woman to her fetus is 60-90%. Blood-borne transmission is now rare due to universal screening of blood products. Untreated individuals remain infectious during the primary and secondary stages.

Transmission Methods:

Direct sexual contact with active lesions
Vertical transmission from mother to fetus (congenital syphilis)
Blood transfusion (rare, screened in modern settings)
Kissing or direct contact with infectious mucous patches

Incubation Period

Typical period: 9-90 days

The incubation period for primary syphilis ranges from 9-90 days, with an average of 3 weeks. The wide variation depends on the size of the inoculum and host immune response. During the incubation period, treponemes are multiplying locally and disseminating via the lymphatics and bloodstream before the appearance of the primary chancre.

Complications of Syphilis

Untreated syphilis can progress to devastating late-stage complications. Cardiovascular syphilis typically appears 15-30 years after infection, causing aortitis, aortic regurgitation, and coronary ostial stenosis. Neurosyphilis can present as asymptomatic CSF abnormalities, meningitis, general paresis (progressive dementia), or tabes dorsalis (sensory ataxia). Congenital syphilis causes stillbirth, neonatal death, or lifelong disability with bone deformities, deafness, and neurological impairment. Syphilitic gummas are destructive granulomatous lesions affecting skin, bones, liver, and other organs.

Possible Complications:

Cardiovascular syphilis (aortitis, aortic aneurysm)
Neurosyphilis (general paresis, tabes dorsalis, meningitis)
Congenital syphilis with multi-organ involvement
Gummatous destruction of skin, bone, and viscera
Increased HIV transmission and acquisition risk

Treatment Options for Syphilis

Parenteral penicillin is the treatment of choice for all stages of syphilis. The preparation, dosage, and duration depend on disease stage. Doxycycline 100mg twice daily for 14-28 days is an alternative for penicillin-allergic patients, though not recommended for pregnant women. The Jarisch-Herxheimer reaction (fever, myalgia, headache) occurs within 24 hours of treatment in 30-50% of patients, particularly in early syphilis. Serological follow-up at 3, 6, 12, and 24 months is essential to confirm treatment response. Sexual partners within the preceding 90 days should be treated presumptively.

Benzathine penicillin G 2.4 million units IM single dose

Single intramuscular dose of benzathine penicillin G 2.4 million units is the standard treatment for early syphilis (primary, secondary, early latent). The gold standard therapy.

Benzathine penicillin G 2.4 million units IM weekly for 3 weeks

Three weekly intramuscular doses of benzathine penicillin G 2.4 million units are required for late latent syphilis and tertiary syphilis without neurological involvement.

Aqueous crystalline penicillin G 18-24 million units daily for 10-14 days

Intravenous aqueous crystalline penicillin G is the regimen for neurosyphilis and congenital syphilis. Requires hospitalization for continuous IV therapy.

Prevention of Syphilis

Syphilis is preventable through consistent condom use, which effectively reduces transmission risk. Regular screening is recommended for sexually active individuals, particularly men who have sex with men, HIV-positive individuals, and those with multiple partners. Universal prenatal screening prevents congenital syphilis. Partner notification and treatment are critical public health interventions. There is no vaccine available. The WHO has targeted syphilis elimination as a public health priority, emphasizing antenatal screening and accessible STI services.

Prevention Measures:

Consistent and correct use of condoms
Regular STI screening for sexually active individuals
Partner notification and treatment
Prenatal syphilis screening for all pregnant women
Safe sexual practices and health education

Important Disclaimer

⚠️This information is for educational purposes only and should not be used for self-diagnosis.
⚠️For accurate diagnosis and treatment, please consult with a qualified healthcare professional at an accredited medical facility.
⚠️Medical procedures and treatments should only be administered by licensed healthcare providers.
⚠️If you suspect you have an STI, visit STD Nepal clinic for confidential testing and treatment.

← Back to Resources