I have a rash ony penis?

RASH ON PENIS. How long has it been there? Does it itch? Does it burn? Is it on the tip or the shaft? Do you use condoms? When does it happen? What soap do you use? I have to know the answers to these questions to be able to help you. Meanwhile use cetaphil cleanser, no condoms (if you do use these), no colognes or other fragrances. Wear boxer not jockey shorts. See a dermatologist if it persists.