Reflectance confocal microscopy for the in vivo detection of Treponema pallidum in skin lesions of secondary syphilis.

BACKGROUND

Secondary syphilis is a diagnostic challenge that relies on microscopic and laboratory tests.

OBJECTIVE

We sought to assess the usefulness of in vivo reflectance confocal microscopy (RCM) to detect Treponema pallidum in lesions suggestive of secondary syphilis.

METHODS

Macular and papular skin lesions from 3 patients clinically suggestive of secondary syphilis were imaged by RCM and confirmed by skin punch biopsy.

RESULTS

In all lesions RCM demonstrated elongated small bright particles with a spiral shape intermingled with the keratinocytes. These features corresponded with immunohistochemical findings that revealed several spirochetes infiltrating the epidermis.

LIMITATIONS

Unlike immunohistochemistry, RCM did not visualize T pallidum in the dermis and vascular walls because of limited imaging depth. The specificity and sensitivity of this technique need to be assessed.

CONCLUSION

RCM may be an effective diagnostic tool for in vivo real-time imaging of T pallidum in skin lesions of secondary syphilis, and seems to correlate well with immunohistochemistry.