The many phases of syphilis
The characteristic lesion of primary syphilis is a chancre, which is a painless, ulcerative lesion with raised borders and a clean, indurated base appearing at the site of spirochete entry (FIGURE 1). Chancres most commonly appear in the genital area, with the most frequent sites in females being within the vaginal canal or on the cervix. Primary chancres tend to heal spontaneously within 3 to 6 weeks, even without treatment, and frequently are accompanied by painless inguinal lymphadenopathy. Given that the most common chancre sites are not immediately apparent, primary infections in women often go undetected.3 In fact, it is essential for clinicians to recognize that, in our routine practice, most patients with syphilis will not be symptomatic at all, and the diagnosis will only be made by serologic screening.
Following resolution of the primary phase, the patient may enter the secondary stage of T pallidum infection. During this stage, spirochetes may disseminate throughout the bloodstream to infect all major organ systems. The principal manifestations of secondary syphilis include a diffuse maculopapular rash that begins on the trunk and proximal extremities and spreads to include the palms and soles (FIGURE 2); mucosal lesions, such as mucous patches and condyloma lata (FIGURE 3); nonscarring alopecia; periostitis; generalized lymphadenopathy; and, in some cases, hepatitis or nephritis.1,3
Secondary syphilis usually clears within 2 to 6 weeks, with the patient then entering the early latent stage of syphilis. During this period, up to 25% of patients are subject to flares of secondary syphilitic lesions but otherwise are asymptomatic.1,3,4 These recurrences tend to occur within 1 year, hence the distinction between early and late latent stages. Once a year has passed, patients are not contagious by sexual transmission and are unlikely to suffer a relapse of secondary symptoms.1,3 However, late latent syphilis is characterized by periods of intermittent bacteremia that allow for seeding of the placenta and infection in about 10% of fetuses.5
Untreated, about 40% of patients will progress to the tertiary stage of syphilis, which is characterized by gummas affecting the skin and mucous membranes (FIGURE 4) and cardiovascular manifestations including arterial aneurysms and aortic insufficiency.3
Neurologic manifestations of syphilis may arise during any of the above stages, though the most characteristic manifestations tend to appear decades after the primary infection. Early neurosyphilis may present as meningitis, with or without concomitant ocular syphilis (uveitis, retinitis) and/or as otic syphilis (hearing loss, persistent tinnitus).1,5 Patients with late (tertiary) neurosyphilis tend to exhibit meningovascular symptoms similar to stroke (aphasia, hemiplegia, seizures) and/or parenchymal effects such as general paresis. Tabes dorsalis (manifestations of which include urinary and rectal incontinence, lightning pains, and ataxia) is a late-onset manifestation.1,3
Congenital syphilis can be subdivided into an early and late stage. The first stage, in which clinical findings occur within the first 2 years of life, commonly features a desquamating rash, hepatomegaly, and rhinitis. Anemia, thrombocytopenia, periostitis, and osteomyelitis also have been documented.5 Of note, two-thirds of infants are asymptomatic at birth and may not develop such clinical manifestations for 3 to 8 weeks.3 If untreated, early congenital infection may progress to late manifestations, such as Hutchinson teeth, mulberry molars, interstitial keratitis, deafness, saddle nose, saber shins, and such neurologic abnormalities as developmental delay and general paresis.3
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