Dermatomyositis Developed After Exposure to Epstein-Barr Virus Infection and Antibiotics Use.

Dermatomyositis is an inflammatory disorder involving muscle and skin. Similar to many other autoimmune diseases, environmental factors appear to trigger the onset of disease in some cases. Many drugs have been reported to be associated with dermatomyositis, and rarely infections have been described as potential triggering agents. Here we are describing a case of dermatomyositis that developed after doxycycline and levofloxacin use, who also had recent Epstein-Barr virus infection. Dermatomyositis associated with doxycycline or levofloxacin use has not yet been described in the literature, while reports of dermatomyositis after Epstein-Barr virus infection have been rare and limited to juvenile dermatomyositis or in association with cancer. It is important for clinicians to be aware of this rare association so that the diagnosis and treatment can be exercised promptly.

Highlighting a Potential Pitfall: Positive Treponema pallidum Immunohistochemical Stain in a Patient Without Syphilis.

The Treponema pallidum antibody immunohistochemical (IHC) stain has improved our ability to detect the organism histologically. We present a case of a man with genital condyloma acuminatum with a positive T. pallidum IHC stain but negative T. pallidum serologies and no syphilitic symptoms. It has been shown that the T. pallidum antibody IHC can cross-react, staining other spirochetes, including Borrelia burgdorferi and the Brachyspira family of intestinal spirochetes. Because of the proximity of our patient's lesions to the anus, and the persistently negative T. pallidum serologies, we believe nontreponemal spirochetes colonized the condyloma, giving a false-positive T. pallidum IHC. This cross-reactivity is a potential diagnostic pitfall and is important for the dermatopathologist to recognize, thereby avoiding false diagnosis of syphilis.