What is the best form of treatment for pityriasis rosea rash?

Time: It can take up to six weeks for the rash to resolve. It rarely recurs, does not scar and does not lead to anything else. An anti-itch bland lotion can help (e.g. Sarna). If you have a rash on your hands/feet, see your doctor because syphilis can be mistaken for pityriasis. Untreated, secondary syphilis can go underground, appear to resolve and cause much worse trouble.

Time: Pityriasis rosea is an especially annoying rash but will eventually go away on its own. It can take several weeks to months to completely resolve. Some studies have shown that sunlight can help speed the resolution of the rash. However, you have to be careful not to have too much sun exposure so you don't get sunburned or cause further damage to your skin. The best thing to do is wait it out.