What adverse reaction can occur after treatment for syphilis?

After treatment for syphilis, particularly with the use of penicillin, a common adverse reaction that can occur is a transient fever. This reaction is associated with the Jarisch-Herxheimer reaction, which can happen after the initiation of treatment for syphilis and other spirochetal infections. The reaction is a result of the rapid lysis of spirochetes, leading to the release of endotoxins and triggering an inflammatory response from the immune system.

Patients may experience symptoms such as fever, chills, malaise, and myalgias, typically occurring within the first 24 hours of treatment. This fever is usually mild and self-limiting, resolving within a short period without requiring further medical intervention. The occurrence of this reaction highlights the importance of informing patients about potential side effects of treatment, ensuring they understand that these symptoms are generally a positive sign that the treatment is working.