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chancre

Chancre

Chancre is a small sore and it is the first sign of syphilis or primary syphilis 1. The sore appears at the spot where the Treponema pallidum syphilis bacteria entered your body. While most people infected with syphilis develop only one chancre, some people develop several of them.

Chancre usually develops about 3 weeks after exposure (range 10 to 90 days) after the acquisition of the infection 2. Many people who have syphilis don’t notice the chancre because it’s usually painless, and it may be hidden within the vagina or rectum. The chancre will heal on its own within three to six weeks.

Chancres progress from a papule to an ulcer, which is typically painless, indurated, well circumscribed, round to oval in shape, with a clean base. The most common sites where chancres develop include the penis (Figure 1), labia, perianal region, or lip/mouth (Figure 2). Regional firm, non-tender, lymphadenopathy often develops in proximity to primary syphilitic lesions (inguinal adenopathy with genital lesions and cervical adenopathy with oral lesions); in most patients, the lymphadenopathy is bilateral 3. Syphilitic chancres are highly infectious and heal spontaneously within 1 to 6 weeks; untreated patients may go on to develop other manifestations of syphilis. Less typical lesions often develop, with one study reporting only 42.7% had a “classic” single lesion. Atypical features may include painful lesions or multiple lesions; in some instances chancres can mimic herpes simplex infection or chancroid 4.

The cause of syphilis is a bacterium called Treponema pallidum. Syphilis usually spreads by touching a chancre sore or wart-like lesions called condyloma lata caused by syphilis. Chancre or condyloma lata may be hard to see, so someone might not know they have them. This can happen through sex (vaginal, oral, or anal) or close sexual contact. The Treponema pallidum bacteria enter your body through minor cuts or abrasions in your skin or mucous membranes. Syphilis is contagious during its primary and secondary stages, and sometimes in the early latent period.

Less commonly, syphilis may spread through direct unprotected close contact with an active lesion such as during kissing or through infected mothers to their babies during pregnancy or childbirth (congenital syphilis).

Syphilis can’t be spread by using the same toilet, bathtub, clothing or eating utensils, or from doorknobs, swimming pools or hot tubs.

Once cured, syphilis doesn’t recur on its own. However, you can become reinfected if you have contact with someone’s syphilis sore.

You face an increased risk of acquiring syphilis if you:

  • Engage in unprotected sex
  • Have sex with multiple partners
  • Are a man who has sex with men
  • Are infected with HIV, the virus that causes AIDS

Without treatment, syphilis can lead to damage throughout your body. Syphilis also increases the risk of HIV infection and, for women, can cause problems during pregnancy. Treatment can help prevent future damage but can’t repair or reverse damage that’s already occurred.

Preventing syphilis

To help prevent the spread of syphilis, follow these suggestions:

  • Abstain or be monogamous. The only certain way to avoid syphilis is to not have (abstain from) sex. The next-best option is to have mutually monogamous sex in which both people have sex only with each other and neither partner is infected.
  • Use a latex condom. Condoms can reduce your risk of contracting syphilis, but only if the condom covers the syphilis sores.
  • Avoid recreational drugs. Misuse of alcohol or other drugs can inhibit your judgment and lead to unsafe sexual practices.
  • If a person has had sex with an infected individual, benzathine penicillin is administered.

Figure 1. Syphilis chancre penis (primary syphilis)

Syphilis chancre penis

Footnote: This patient with primary syphilis had a large firm ulcerated lesion on the penis accompanied by right-sided inguinal adenopathy.

Figure 2. Chancre on lip (primary syphilis)

Footnote: This man with primary syphilis developed an oral chancre at the lower lip. Syphilitic chancres are typically round, firm, and painless.

Primary syphilis chancre diagnosis

Evaluation of patients with genital ulcers should include dark-field microscopy and serological tests for syphilis and a diagnostic evaluation for genital herpes. In addition, if available, suspected primary syphilis should be evaluated with darkfield microscopy or a polymerase chain reaction (PCR) test for Treponema pallidum. In geographic regions where chancroid is endemic (Asia, Africa, and the Caribbean), testing for Haemophilus ducreyi should also be performed.

Dark-field examination by microscope allows for direct examination of spirochetes from the mucosal lesion and thus offers an immediate diagnosis 5.

The serological tests are classified as non-treponemal and treponemal. The non-treponemal tests (venereal disease research laboratory tests [VDRL], rapid plasma reagin test [RPR]) are screening tests that detect antibodies to cardiolipin in blood. The VDRL and RPR tests are only positive after the development of the primary chancre.

Positive non-treponemal tests are confirmed with treponemal tests (fluorescent treponemal antibody absorption assay, Treponema pallidum particle agglutination assay) that detects antibodies to the Treponema pallidum in blood. Syphilis is a reportable disease.

Patients with neurologic symptoms should undergo cerebrospinal (CSF) examination.

All patients with syphilis should be tested for other sexually transmitted diseases (STDs). In addition, today syphilis is routinely tested during the first trimester of pregnancy. If the testing is positive, benzathine penicillin G is administered.

Imaging studies depend on the organ involved. Chest x-ray may be the first clue to the presence of an aortic aneurysm. A CT scan can confirm this. Echo is needed to rule out aortic regurgitation.

Reverse sequence screening is an increasingly used algorithm across US laboratories that use treponemal tests as the initial screening to identify those patients with treated, untreated, or incompletely treated syphilis 6. Because of a lack of validation of the reverse algorithm, higher rates of false-positive results can be seen leading to difficulty in interpreting these tests and the need for second confirmatory treponemal tests.

Chancre treatment

Treatment depends on the syphilis stage.

Primary, secondary or early latent syphilis is treated with a single dose of intramuscular (IM) penicillin G benzathine 2.4 million units. Alternative therapies include doxycycline 100 mg orally (PO) twice daily for 14 days or ceftriaxone 1 to 2 gm IM or intravenously (IV) daily for 10 to 14 days or tetracycline 100 mg orally 4 times daily for 14 days.

Late latent syphilis is treated with IM penicillin G benzathine 2.4 million units once weekly for 3 weeks. Alternative therapies include doxycycline 100 mg PO twice daily for 28 days or tetracycline 100 mg orally four times daily for 28 days.

Tertiary syphilis is treated with IM penicillin G benzathine 2.4 million units once weekly for 3 weeks.

Neurosyphilis is treated IV penicillin G aqueous 18-24 million units daily for 10 to 14 days.

Patients with a high titer of secondary syphilis can develop Jarisch-Herxheimer reaction, which is an immune-mediated self-limited reaction that occurs within 2 to 24 hours of treatment and is characterized by high fever, headache, myalgias, rash.

Patients need to be followed post-treatment at 3, 6, 9, 12, and 24 months with serial non-treponemal tests. A 4-fold decline in these tests indicates successful treatment 7.

Jarisch Herxheimer reaction

Following treatment with penicillin, the dying organisms often release inflammatory cytokines that lead to the Jarisch Herxheimer reaction. The symptoms include headache, muscle pain, fever, tachycardia, and malaise. The reaction usually appears within 24 hours of starting treatment. The treatment is supportive. Pregnant women who develop this reaction need to be observed closely as it can lead to obstetric complications.

References
  1. Lafond RE, Lukehart SA. Biological basis for syphilis. Clin Microbiol Rev. 2006;19:29-49.
  2. Hook EW 3rd, Marra CM. Acquired syphilis in adults. N Engl J Med. 1992;326:1060-9.
  3. Watts PJ, Greenberg HL, Khachemoune A. Unusual primary syphilis: Presentation of a likely case with a review of the stages of acquired syphilis, its differential diagnoses, management, and current recommendations. Int J Dermatol. 2016;55:714-28.
  4. Chapel TA. The variability of syphilitic chancres. Sex Transm Dis. 1978;5:68-70.
  5. Tudor ME, Al Aboud AM, Gossman WG. Syphilis. [Updated 2019 Oct 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534780
  6. Cohen SE, Klausner JD, Engelman J, Philip S. Syphilis in the modern era: an update for physicians. Infect. Dis. Clin. North Am. 2013 Dec;27(4):705-22.
  7. Tipple C, Taylor GP. Syphilis testing, typing, and treatment follow-up: a new era for an old disease. Curr. Opin. Infect. Dis. 2015 Feb;28(1):53-60.
Health Jade Team

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