Dermatology Questions? Ask an Online Dermatologist.
Thanks for your question.
What tests you have had?
Can you upload a photo of the red mark here using the paper clip icon in the toolbox?
Thanks for your reply.
You need to get tested for syphilis.
Primary syphilis can appear with a lesion on penis which usually starts with a raised papule which ulcerates later on .Usually appears at around 3 weeks after exposure.
The appearance of the lesion is not characteristic of chancre of syphilis but location and time of appearance of lesion makes it imperative that you should have yourself tested for syphilis as well.
This is my initial answer.Please reply if you need any clarification.
The initial VDRL test can be done 2 weeks after chancre formation.
Depending upon the VDRL result further testing can be done.
Primary syphilis is usually symptom less.Only signs are formation of chancre and enlargement of lymph nodes in the area.Lymph node enlargement can be detected by your doctor on examination.
As I mentioned in my first post, the lesion is not characteristic of a chancre but because of spontaneous appearance and site and time of appearance you need to get tested to rule out syphilis.
Antibiotics can interfere with blood clotting and it is possible that this is spontaneous bruising as a result of antibiotic you are taking.Only caveat here is that bruising has appeared only on penis which is unusual.Still antibiotics have to be considered as culprit here.
It would be a good idea to have a doctor examine you and order relevant tests like coagulation profile.