Syphilis infection with ANA positivity: case series

Infections frequently mimic rheumatological disorders, posing significant diagnostic challenges. Syphilis, in particular, is a well-recognised "great mimicker" due to its diverse clinical presentations that can closely resemble various autoimmune and inflammatory rheumatic conditions. In such cases, careful consideration of the patient's symptoms and history is crucial to differentiate between conditions that may present similarly. Prompt recognition of syphilis in the early stage provides the best opportunity to prevent associated complications. This is a retrospective case series of five cases presented to the Department of Clinical Immunology and Rheumatology at a tertiary care hospital between 2023 and 2024. We report five cases that initially presented with either maculopapular rash, arthralgia or both and anti-nuclear antibody (ANA) positivity, which raised suspicion of an Autoimmune Rheumatic Disease (AIRD). However, upon further evaluation, these cases were diagnosed with syphilis. These cases underscore the importance of comprehensive evaluation and consideration of infectious causes, like syphilis, in the differential diagnosis of cases with symptoms of AIRD, where the use of immunosuppression can be devastating.