So what’s so sneaky about it? According to the Centers for Disease Control and Prevention (CDC), the appearance of a single sore marks the primary stage of Syphilis symptoms, but there may be multiple sores. The sore appears at the location where Syphilis entered the body. The sore is usually firm, round and painless. Because the sore is painless, it can easily go unnoticed. It lasts three to six weeks and heals regardless of whether or not a person is treated. However, if the infected person does not receive adequate treatment, the infection progresses to the secondary stage, which usually starts with a rash on one or more areas of the body.
If the infection continues to go untreated, Syphilis can progress and cause long-term complications and/or death. For more information on this common STD, check out this fact sheet from the CDC.