Hi. I sometimes small red spots or bumps appear on my scrotum/base of penis that last about 4 days then disappear. I had a doctor look at one red spot and he says it doesn t appear to be an std . I have itching and tingling in my scrotum and was wondering if there is anything else that can cause this. I had a full blood/ urine test with negative results but maybe I got the test too soon? What else can cause this? Some of the red spots are at the base of a pubic hair . Thanks.