###Human: How can the symptomless ulcer at the back of penile shaft be treated? ###Assistant: Hi. I have gone through your case. According to your description and clinical picture (attachment removed to protect patient identity), this ulcer could be a manifestation of primary chancre of syphilis (one of the sexually transmitted diseases, if there is a history of sexual contact as well at least 3 to 4 weeks ago). Sexually transmitted infection syphilis. VDRL, TPHA, test for other STD like hepatitis B and C, HIV. Traumatic. Primary chancre of syphilis. Benzathine penicillin 1.2 MU I/M on each buttock stat dose. If tests are normal then only Fucidin acid cream two times a day.