What Causes Itching And Red Spots In Penis?

For past 3-4 months i started getting some unusual sympstoms in my penis.
I dont know how to put them. I get some red spots or Bruises and most of the time it itches like hell which is very much
uncomfortable. I met a general dr in chennai, he took random sugar test and urine test and said nothing to worry and
prescribed a oinment which helped for few days. but after sometime it comes again.. i dint use that oinment for almost 2 months.