Syphilis, caused by the spirochete Treponema pallidum, manifests in distinct stages with characteristic skin lesions visible in clinical images. This gallery covers primary, secondary, and tertiary syphilis presentations to aid diagnosis.
Primary Syphilis
Primary syphilis typically presents 10–90 days post-infection (average 21 days) with a painless chancre at the inoculation site. The ulcer has raised, indurated borders and a clean base, allowing T. pallidum to invade via its spiral motility. Chancres occur on genitals, anus, mouth, or other mucocutaneous sites and heal spontaneously in 3–6 weeks if untreated.
- Genital chancre: Single or multiple painless ulcers on penis, vulva, or cervix with sharp margins.
- Oral chancre: Firm sores on lips, tongue, or buccal mucosa, often mistaken for trauma.
- Anal chancre: Circular ulcer in perianal region, associated with regional lymphadenopathy.
Images reveal well-defined borders distinguishing chancres from herpes (vesicular) or chancroid (painful, purulent). Dark-field microscopy or PCR from lesion swabs confirms spirochetes.
Secondary Syphilis
Secondary syphilis arises 4–10 weeks after primary, due to hematogenous dissemination. It features a generalized, non-pruritic rash and systemic symptoms like fever, malaise, lymphadenopathy, and sore throat. The patient is highly infectious. Rash resolves in weeks but may recur.
Characteristic rash includes maculopapular, papular, pustular, or squamous lesions, often coppery-red, 0.5–2 cm, involving trunk, extremities, palms, and soles—a hallmark feature.
- Palmar/plantar rash: Symmetrical erythematous macules or plaques on palms and soles, non-scaly or finely scaly.
- Generalized rash: Bilateral maculopapular eruption on trunk, arms, legs; may be macular, papular, or pustular.
- Mucous patches: Painless, silver-white plaques on oral or genital mucosa with erythematous halo, teeming with spirochetes.
- Condylomata lata: Broad, moist, flat-topped plaques in intertriginous areas (genitals, anus, axillae); highly infectious, wart-like but flatter than viral warts.
- Corymbose syphilis: Rare ‘flower-like’ pustules surrounding central plaque.
- Alopecia: Moth-eaten patchy hair loss on scalp.
Serology (RPR/VDRL + treponemal tests) is positive; prozone effect may cause false negatives in high-titer cases. PCR from moist lesions enhances detection.
Tertiary Syphilis
Tertiary syphilis develops 1–30 years post-infection in 15–30% untreated cases, involving gummatous, cardiovascular, or neurosyphilis. Skin shows gummas: destructive granulomatous ulcers or nodules with serpiginous borders, healing with atrophic scars.
- Gummatous ulcers: Heaped-up, crateriform lesions on skin or mucosa.
- Nodular gummas: Firm subcutaneous masses eroding to ulcers.
Images depict irregular, punched-out ulcers distinguishing from malignancy or TB. Diagnosis via biopsy and serology; responds to penicillin.
Diagnosis and Testing
Diagnosis combines history, exam, and labs. Direct detection: dark-field microscopy or PCR from chancre/exudate (sensitivity 80–95% primary). Serology: Nontreponemal (RPR/VDRL) for activity/staging; treponemal (FTA-ABS, TPPA) for confirmation.
| Stage | Lesion Swab PCR | Serology |
|---|---|---|
| Primary | Yes | May be negative early |
| Secondary | Yes (moist lesions) | Always positive |
| Tertiary | No | Positive |
| Latent | No | Positive |
Post-exposure screening at 6/12 weeks; treat with benzathine penicillin G.
Frequently Asked Questions (FAQs)
Q: Is the syphilis rash itchy?
A: No, the secondary syphilis rash is typically non-pruritic, unlike many dermatoses.
Q: Can syphilis be diagnosed from images alone?
A: Images guide suspicion, but confirm with PCR/serology due to mimics like HIV rash or psoriasis.
Q: What do primary chancres look like?
A: Painless, indurated ulcers with clean base and raised edges on genitals/mouth.
Q: Are condylomata lata contagious?
A: Yes, highly infectious due to abundant spirochetes; distinguish from warts by moist, flat appearance.
Q: How is palm/sole rash diagnostic?
A: Unique to secondary syphilis among STIs; coppery macules confirm with serology.
On DermNet
Explore related topics: Syphilis, Chancre, Condyloma Lata.
Books about Skin Diseases
- Rook’s Textbook of Dermatology
- Andrews’ Diseases of the Skin
- IADVL Textbook of Dermatology
Other Recommended Articles
- STIs overview
- Dark-field microscopy
- Syphilis serology
References
- Syphilis – DermNet — DermNet NZ. 2023. https://dermnetnz.org/topics/syphilis
- Skin rash and lesions – general | STI Guidelines Australia — STI Guidelines Australia. 2023. https://sti.guidelines.org.au/syndromes/skin-rash-and-lesions-general/
- Syphilis rash: Pictures, symptoms, treatments, and more — Medical News Today. 2023-10-20. https://www.medicalnewstoday.com/articles/syphilis-rash
- PCR swabs: a useful diagnostic tool for identifying syphilis — This Changed My Practice. 2023. https://thischangedmypractice.com/pcr-swabs-diagnostic-tool-identifying-syphilis/
- Syphilis Symptoms and Signs — STDcenterNY. 2023. https://stdcenterny.com/syphilis-symptoms-and-signs.html
- Syphilis images – DermNet — DermNet NZ. 2009. https://dermnetnz.org/topics/syphilis-images
- Syphilis Pics Secondary — Oklahoma.gov. 2023. https://oklahoma.gov/content/dam/ok/en/health/health2/aem-documents/prevention-and-preparedness/sexual-health-harm-reduction/syphilis-resources/syphilis-pics-secondary.pdf
- Syphilis image – DermNet — DermNet NZ. 2023. https://dermnetnz.org/imagedetail/7957-syphilis
