Can Pityriasis Rosea Infection Spread To Penis?

is it possible for pityriasis rosea to spread to penis? because i m having p.rosea since 3 weeks now... and today morning i noticed two or three dark spots on my glans too. how much time p.rosea will take to disappear. by the way i dont have that much itching thats why i am not taking any treatment. should i take any treatment?