A 48-year-old woman with red eyes and a rash

Patients are often referred to an allergist/immunologist as part of a comprehensive evaluation for multiple, varied complaints, some of which are neither allergic nor immunologic in origin. This patient was seen at numerous outpatient clinics with a series of assorted complaints before definitive diagnosis, highlighting the need to pursue a broad differential diagnosis. The constellation of findings of a diffuse rash, uveitis, and laboratory evidence of an acute inflammatory process should raise the clinical suspicion for a systemic process other than allergic disease. Syphilis, the "great imitator," should be in the differential diagnosis of any patient with multiple systemic symptoms of unknown origin. Unfortunately, the absence of pathognomonic signs and the known ability of syphilis to mimic any systemic inflammatory disease can often lead to misdiagnosis, or nondiagnosis, with a resultant delay in appropriate therapy. Although it is true that before the 1930s ocular syphilis was considered to be one of the most common causes of intraocular inflammation, such is not the case today. As a result, modern clinicians are less likely to include this disease in their differential diagnosis. A comprehensive history and physical examination can help.