What Causes A Rash On The Penis?
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Detailed Answer:
Hello and welcome,
Without a good quality photo, I can't tell you exactly what it is, and rashes are best examined by a physician in person. But it is possible that it is a yeast infection of the skin as this is a common cause of skin rashes of the genitals in either sex.
Best to have it seen in person, but if you cannot, you can try an over the counter anti yeast/antifungal cream which you can buy without prescription at a drug store.
If it is a yeast infection, keep the area as dry as possible such as by wearing loose fitting cotton boxer shorts, changing these if they get sweaty, and after showering, XXXXXXX skin dry with towel then use hair blow dryer on low setting to dry further.
If you have a partner who has any yeast infection symptoms (vaginal discharge, itching) she should be treated too so that the infection doesn't recur.
But again, I am guessing as I can't (and really no one can) tell what the rash is for sure without seeing it.
I hope this information helps.