Timothy C. Hain, MD Return to Index. • Page last modified: July 2, 2022

Main Points:

Syphilis is presently making a comeback in the United States, especially in men who have sex with men(Theeuwen et al, 2019). As of 2014, there were 55,000 new cases/year (Clement et al, 2014). The increase is not confined to men. In 2019, the rates of early syphilis among women of reproductive age increased from 2.5 to 15.1 per 100,0000 population (Stafford et al, 2019). With inclusion of late-stage syphilis, cases among women in this age group increased from 7870 to 18440 (ie. roughly doubled). Interestingly, although great progress has been made in reducing HIV infection, the number of cases of syphilis is climbing rapidly over the last decade (i.e. 2010-2019).

Syphilis is caused by infection with Treponema Palladium, a spirochete. Another spirochete illness is Lyme disease. It also can affect the ear. Syphilis usually is spread through contact with infectious lesions or body fluids, and generally through sexual contact.

In 2013, more than 16,000 of the reported cases were primary and secondary syphilis, and 3/4 of these were in men who have sex with men (Clement et al, 2014). Primary and secondary syphilis disproportionately affects black men, whose infection rate is more than 5-fold higher than white men. About 50-70% of patients with primary or secondary syphilis, also are HIV positive.


About 21 days after exposure, patients develop a skin lesion called a chancre at the site of exposure. These are often on the sexual organs. Syphilitic chancres are typically non tender, hard, non-purulent ulcers. The chancres typically heal without therapy. This is called primary syphilis.

Secondary syphilis begins 4-10 weeks after the chancre. A rash is the main complaint. It often affects the hands and or soles. The rash is rarely vesicular (blistering). There are many less specific findings such as sore throat, headache and the like. Secondary syphilis can cause neurologic, renal, ophthalmologic, gastrointestinal and hepatic disease. Secondary syphilis again, typically resolves without treatment.

There may then be a latent period, with reappearance of symptoms late in the course. The reappearance is called late or tertiary syphilis. In Tertiary syphilis, patients may develop cardiovascular symptoms (such as aortitis), gumma's, and neurosyphilis. Neurosyphilis may include general paresis (a type of dementia) and tabes dorsalis (a spinal cord disease)


Otosyphilis can closely resemble Meniere's disease, perilymph fistula, sudden hearing loss, autoimmune inner ear disease, and bilateral vestibular loss. Because the inner ear communicates with spinal fluid via the cochlear aqueduct, otosyphilis is a variety of neurosyphilis and neurological symptoms are also possible.

Early neurosyphilis mainly presents as meningitis with or without cranial nerve involvement and meningovascular disease or stroke. Hearing symptoms of early neurosyphilis might be a sudden hearing loss.

Late neurosyphilis may affect the brain (general paresis), or spinal cord (tabes dorsalis). In the ear, late neurosyphilis may present as hearing loss, fluctuating hearing, or vestibular imbalance/weakness (vertigo).

Pathologic studies of syphilitic ears report hydrops in most. In addition, there is a loss of type II vestibular hair cells in the otoliths and semicircular canals (Hizli et al, 2015)


There are several methods of diagnosing syphilis. The non-treponemal serologic tests are the RPR (rapid plasma reagin) and VDRL. Treponemal tests include FTA-abs (Fluorescent treponemal antibodies).

False positives occur in 1-2% of the US population, and are associated with autoimmune diseases, other infections, and IV drug use.

False negative tests can appear in persons with very high titer RPR or VDRL tests (the titer is too high to measure) as well in immunosuppressed people.

Although conventional teaching is that RPR/VDRL tests go negative after treatment, and FTA tests persist forever, there are numerous exceptions to this general rule.

Neurosyphilis and otosyphilis are diagnosed by CSF pleocytosis (increased cell count) or elevated spinal fluid protein, reactive CSF RPR, or identification of T-pallidum in CSF by PCR or by infectivity in rabbits.

Many patients with syphilis have HIV and testing for this should be considered in a person with syphilis. Testing for other STD's such as gonorrhea and chlamydia is also recommended.


The treatment of otosyphilis is the same as the treatment of neurosyphilis. The CDC recommends aqueous penicillin G, 18-24 million units/day administered as 3-4 million units IV every 4 hours or continuously, for 10-14 days. Alternatively, procaine penicillin 2.4 million units may be given IM daily plus probenecid 500 mg by mouth, 4 times/day, both for 10-14 days. It is been postulated that treponemes divide more slowly in the late infections, justifying the longer treatment than for primary (see below).

Persons with non-life threatening allergies to Penicillin should ideally be desensitized.

In general, a 4-fold decline in the nontreponemal titer (such as RPR or VDRL), is needed to signify treatment response. There has never been a case of penicillin resistance by syphilis documented over 60 years.

Primary and secondary syphilis is generally treated with a single dose of 2.4 million units of Benzathine penicillin (Clement et al, 2014).

About 10-15% of patients treated for syphilis develop the Jarisch-Herxheimer reaction -- which manifests with a febrile illness within 24 hours of treatment. This occurs in 10-35% of treated patients. It is an immune reaction to killed treponemes.

Treatment followup and prognosis.

According to Goldman (2003), all patients require clinical and blood testing followup 6 and 12 months after treatment. Patients with HIV should also be evaluated at 3, 9 and 24 months after treatment. Treatment failure is defined as failure of RPR/VDRL to decline by at least 2 dilutions within 6 months of treatment, or a sustained 4-fold increase in RPR/VDRL at some point after treatment. If treatment failure is not noted, all patients with otosyphilis should undergo repeat CSF examinations at 3 and 6 months following therapy and then every 6 months until CSF is normal.

The "serofast" state refers to a situation where RPR or VDRL decline but fail to completely revert to nonreactive. About 15-41% of treated patients remain serofast (Clement et al, 2014).

In the study of Gleich et al, hearing responded in only about 35%. (1992). Vertigo improved to a much greater extent. Hearing may respond initially but relapse (Dobbin and Perkins, 1983). In congenital syphilis, hearing may not show any lasting improvement.