3. Discharge from the Penis
Discharge from the penis is symptomatic of multiple STDs, including chlamydia, gonorrhea, and trichomoniasis. The discharge associated with gonorrhea is often thick, cloudy, or bloody. Discharge accompanied by abdominal pain suggests a chlamydia infection, while trichomoniasis causes an odorous discharge. Like many STD symptoms, there are other possible causes for penile discharge, but STDs are the most common culprits.