What causes redness at the male urethral opening?

Redness at the male urethral opening may be caused by various factors, including physiological structural differences, local irritation, insect bites, urethritis, prostatitis, gonococcal urethritis, fungal urethritis, urethral calculi, and balanoposthitis. Among these, the most common cause is infection, such as infections by bacteria, viruses, mycoplasma, or chlamydia. In addition, unhealthy lifestyle habits, such as wearing tight underwear or cycling for prolonged periods, may also reduce the resistance of the urethral mucosa, leading to inflammation. If redness and swelling at the urethral opening persist or are accompanied by other symptoms such as pain, difficulty urinating, or discharge, prompt medical attention should be sought.