Pityriasis rosea is a skin condition that causes a rash, defines WebMD. The cause of pityriasis rosea is unknown, as of 2015. It is most often found in people between the ages of 10 and 35.
Pityriasis rosea is generally harmless, but it can cause rare issues in pregnant women, such as premature delivery or miscarriage. The rash that occurs from pityriasis rosea typically lasts from six to eight weeks, explains WebMD. The rash begins with one circular pink patch that is flaky with a raised border. More patches soon appear over the back, chest, legs, arms, and abdomen in the days and weeks that follow. These patches may itch for about half of the people with the rash. The rash may appear in blister form for infants and young children.
Pityriasis rosea is diagnosed by sight, but a potassium hydroxide test is sometimes used to be sure that it is not caused by a fungal infection, states WebMD. A test for syphilis may also be done on a sexually active person. The rash disappears on its own, but skin lotions, lubricants and anti-inflammatory medicines can be used to reduce itching. Gentle soaps should only be used on the skin to avoid irritation, and hot showers and baths are not recommended.