Rapid progression of a painful vulvar lesion in a multiple sclerosis patient on ocrelizumab: A case report

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. Immunomodulatory therapies are frequently employed in disease management, but they may increase susceptibility to infections. A patient with MS on ocrelizumab presented with a rapidly progressing paraclitoral lesion. Serological tests for Treponema pallidum were initially negative, but a wedge excision of the lesion tested positive for syphilis. Ocrelizumab may interfere with the serological diagnosis of infectious diseases such as syphilis. This case underscores the need for heightened vigilance in diagnosing patients on immunomodulatory therapies, especially when they remain seronegative for syphilis.