Blake St. Clair

Author Bio -

Key Points:

*Sexually transmitted infection with Treponema pallidum

*Stages of syphilis are divided into primary, secondary, latent, and tertiary syphilis

*Primary syphilis refers to a painless ulcer called a chancre that appears on the genitals or other mucosa, whereas secondary syphilis refers to a generalized rash that classically includes the palms and soles.  Tertiary syphilis features gummas, which are rubbery nodules of the skin

*There is also a congenital form of syphilis in which an infected mother passes the infection to her baby

Syphilis occurs whenever the bacteria Treponema pallidum infects someone, typically after sexual contact with an ulcer contaminated with Treponema.  The primary stage of syphilis is marked by the appearance of a chancre, a painless ulcer that appears a few weeks after exposure to the bacteria.  A chancre ulcer will heal on its own over the course of a few months, but it is highly infectious before it heals and not recognizing and treating syphilis at this stage can lead to secondary syphilis.  Secondary syphilis will appear a month or two after the primary chancre heals, and a maculopapular (small, round lesions that are flat or slightly raised) rash that is generalized but often involves the palms and soles.  Latent syphilis may then occur, which is a hibernating stage of the disease where no physical symptoms occur.  A subset of those patients may go on to develop tertiary syphilis years later, which presents with a remarkable variety of problems including severe cardiac and nervous system disease.  Tertiary syphilis is also characterized by the formation of gummas, subcutaneous granulomas which form large rubbery nodules on the skin.

Differential Diagnosis

Primary syphilis- Ulcers that may mimic a chancre ulcer include other sexually transmitted diseases such as Herpes Simplex, chancroid (Haemophilus ducreyi infection), and lymphogranuloma venereum (Chlamydia trachomatis infection)

Secondary syphilis- Pityriasis Rosea, Guttate Psoriasis, Drug Eruption


*A single, painless genital ulcer is highly suspicious of primary syphilis or chancre

*Biopsy and silver stain or dark-field microscopy allow direct visualization of T pallidum

*A maculopapular rash with palm and sole involvement and a recent history of a single, painless genital ulcer is very suggestive for syphilis

*Blood tests include RPR, VDRL, and FTA-ABS

The diagnosis of primary syphilis/chancre is suggested in someone with a single, painless genital or oral ulcer and a recent history of unprotected sexual contact.  Screening of syphilis is done with RPR and VDRL, serum tests that catch the vast majority of syphilis infections but have a some false positives.  For this reason, confirmation of a positive RPR or VDRL may be done using a blood FTA-ABS which looks for anti-treponemal antibodies in the blood.  If the diagnosis remains unclear, syphilis can be confirmed by tissue biopsy and silver staining or swabbing and dark-field miscroscopy.  Secondary and tertiary syphilis are suspected if typical skin findings are present. 


*Penicillin is the mainstay of syphilis treatment

*Early treatment prevents late complications of the disease

All stages of syphilis are treatable with the antibiotic penicillin, but alternatives are available for those who are allergic to this drug.

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