Pityriasis rosea is a rash that can occur at any age but it occurs most commonly in people between the ages of 10 and 35 years. The rash can last from several weeks to several months. Usually there are no permanent marks as a result of this disease.

The condition often begins as a large single pink patch on the chest or back. This patch may be scaly and is called a "herald" or "mother" patch. Often the person with this condition will think this patch is a ringworm and will apply creams that are used to get rid of fungus. This will not help since the rash is not caused by a fungus.

Within a week or two, more pink patches, sometimes hundreds of them, appear on the body and on the arms and legs. Patches may also occur on the neck, and though rare, the face. These spots usually are smaller than the "herald" patch and may also be mistaken for ringworm. The patches are oval and often form a pattern over the back that resembles the outline of a Christmas tree. Sometimes the disease can produce a more severe and widespread skin eruption. About half the patients will have some itching, especially when they become overheated.

The rash usually fades and disappears within six to eight weeks, but can sometimes last much longer. Physical activity-like jogging, running, or bathing in hot water may cause the rash to temporarily worsen or reappear.

What is the cause of this skin disorder?

The cause is unknown. It is not caused by a fungus or bacteria. It also is not due to any type of allergy. Pityriasis rosea is not a sign of any internal disease.

A virus may cause this rash; however, pityriasis rosea does not seem to spread from person to person.

What is the treatment?

Treatment is often not necessary. Soothing medicated lotions and lubrication are recommended. Lukewarm rather than hot baths may be suggested. Strenuous activity that could aggravate the rash should be avoided. If the rash itches, prescription creams usually bring relief. UV light treatments can be given for more extensive rashes.

Remember that pityriasis rosea is a common skin disorder and is usually mild. Most cases usually do not need treatment and, fortunately, even the most severe cases eventually go away.