What Causes Redness And Swelling On The Glans Of Penis?

Two weeks after unprotected vaginal sex (I'm male, 48), I experienced redness and some puffiness around the urethral meatus. The redenss extends to the underside of the glans. I had no discharge and no burning upon urination. I have periodic mild pain in my penis tip.



I was tested for Chlamydia, Gonnoreah, Trichonomoniasis, and several types of yeast. All were negative. (real-time PCR urine test).



I was prescribed Zithromax, but the symptoms persist.



One urologist called it "local irritation".



I have had this condition for 2.5 weeks.



Ideas?