Although syphilis is one of the oldest known diseases, most health
professionals do not have access to the tests necessary to reliably
diagnose it in its earliest and most infectious stage. A recent survey
of infectious diseases specialists regarding the diagnosis and treatment
of syphilis appears in the November 15, 2009 issue of Clinical Infectious Diseases, now available online.
Definitive
diagnosis of primary syphilis (the earliest stage of syphilis
infection) relies on direct fluorescent antibody testing or darkfield
microscopy, both of which are often unavailable in a clinical setting.
Blood tests are commonly used to diagnose syphilis; however those tests
produce false negatives in 20-30 percent of primary syphilis cases,
allowing for the possibility of ongoing transmission.
According to
study author Deborah Dowell, MD, of the Centers for Disease Control and
Prevention (CDC), “Eighty-one percent of our survey respondents did not
have access to darkfield microscopy. These clinicians should treat
presumptively if they suspect early syphilis in their patients.” Dr.
Dowell also notes that there is a clinical and public health need for a
rapid point of care test to reliably diagnose primary syphilis.
The
survey also shows that most respondents treat HIV-positive patients who
have secondary syphilis with three weekly penicillin injections
although there is no evidence of improved outcomes for treating with
more than one injection. Physicians with more syphilis management
experience were more likely to treat with the recommended one injection,
which suggests that physicians with less experience managing syphilis
may lack confidence that management according to established guidelines
is sufficient to prevent adverse outcomes.
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