Dermatitis can refer to many different skin conditions. Flu-like symptoms may also occur. The main cause of having dry skin on your penis is masturbating too roughly, too often, or without Dry area on penis lubricant. There are multiple conditions that can cause a rash on the penis or in the groin. September 8, at 7: If tight clothes are constantly worn around the genital area, they can chafe or rub against the skin, and lead to dryness.