Syphilis affects millions of people each year, and its incidence has increased year on year over the last 10 years. Traditionally, the diagnostic algorithm for syphilis started with a nontreponemal test (NTT) (rapid plasma reagin [RPR] test or Venereal Disease Research Laboratory [VDRL] test). Only if one of these tests was positive would specific treponemal tests (TTs) (Treponema pallidum hemagglutination, fluorescent treponemal antibody absorption, or T. pallidum particle agglutination tests) be requested for confirmation. In recent years, automated treponemal tests (enzyme-linked immunoassay [EIA] and chemiluminescent immunoassay [CLIA]) have been developed, with high sensitivity, rapid test performance, and observer-independent results. These tests should now be considered for use as screening tools, especially as they are inexpensive.

These developments have led to replacement of the traditional diagnostic algorithm for syphilis (NTTs first then TTs) with others that place emphasis on the automated treponemal tests. Such an algorithm is proposed by the European Centre for Disease Prevention and Control (ECDP) in its most recent update to the guidelines. The recommendation now is to start with an automated TT (EIA and CLIA) and subsequently perform a quantitative NTT (RPR). If the NTT is negative, a second TT different to the one previously used for screening is employed.1

The new automated techniques also allow measurement of IgM and IgG antibodies specific for T. pallidum, which is of particular interest for monitoring therapeutic response as IgM levels decrease rapidly after suitable treatment; these tests are particularly useful for follow-up of response in patients with HIV coinfection.2

It is essential that dermatologists be aware of the important progress in diagnostic tests and the resulting changes in the diagnostic algorithm for syphilis. The study by García-Legaz Martínez et al.3 highlights how these new diagnostic approaches are extremely useful in everyday clinical practice. Our obligation is to keep up to date in this field, not only because venereology is an essential part of our specialty, but also to avoid mistaken interpretations in tests requested, or diagnostic errors or inappropriate follow-up of our patients.