Like hives and everything else on this list, pityriasis rosea begins with large, raised red patches of skin. Pityriasis rosea may also come with a headache, fever, sore throat and stuffy nose. At the outset, pityriasis rosea begins with a herald patch, often confused for both hives and ringworm. As it progresses, it spreads around the initial patch with small, scaly spots resembling a pine tree [source: American Osteopathic College of Dermatology].
The cause of pityriasis rosea is unknown. No bacteria, fungus or virus has been attributed to its onset [source: Lichenstein]. It is possible that certain types of herpes may play a role, but no definitive cause has been found.
Generally, pityriasis rosea will go away on its own in four to six weeks, but in certain cases, a doctor may treat the rash. Certain antiviral medications are known to reduce the duration by a couple weeks, but usually oral antihistamines and steroid creams are prescribed to help counter the itching.
If you'd like to learn more about hives or other skin infections, you'll find more information on the next page.