[Fever in systemic lupus erythematosus: disease exacerbation or infection?]

The differential diagnosis of fever, especially in the context of autoimmune diseases is broad. Accordingly, the spectrum of diagnostic procedures is extensive and the therapeutic consequences are partly contradictory. Fever is basically the manifestation of an increased cell proliferation, such as classically seen in tumors, infections or autoimmune inflammation. Systemic lupus erythematosus (SLE) is one of the most multifaceted rheumatological diseases. Fever is one component of the new classification criteria which help to classify and possibly diagnose SLE. The differential work-up of fever is a special challenge for clinicians particularly in the context of the initial diagnosis of SLE or another autoimmune disease and also in the course of the disease in patients with autoimmune diseases. Based on a case report this article discusses differential diagnostic considerations and proposes a concrete differential diagnostic procedure. The patient's history is highlighted as an extremely important source of relevant information. Without claiming completeness various factors are listed, which help to differentiate fever as a consequence of SLE activity versus fever as a consequence of an infection.