Pityriasis (rash inflammatory skin)

Skin | Dermatology | Pityriasis (rash inflammatory skin) (Disease)


Description

Pityriasis rosea is a common, relatively short-lived skin disorder exhibiting a scary rash of symmetrical pink patches. Doctors do not think that pityriasis rosea is contagious, but the cause is unknown. Some experts suspect the rash, which is most common in spring and fall, may be triggered by a virus, but no infectious agent has ever been found.

It is not sexually transmitted, and does not appear to be contagious from one person to the next.

Sometimes, before the symptoms appear, people experience preliminary sensations including fever, malaise, sore throat, or headache. Symptoms begin with a single, large round spot called a herald patch on the body, followed days or weeks later by slightly raised, scaly-edged round or oval pink-copper colored spots on the trunk and upper arms. The spots, which have a wrinkled center and a sharp border, sometimes resemble a Christmas tree. They may be mild to severely itchy, and they can spread to other parts of the body.

Causes and Risk factors

The underlying cause of Pityriasis is unknown, but an unidentified virus is believed to be the culprit. Even so, it is not contagious. Pityriasis typically occurs during the spring and autumn months and affects mostly adolescents or young adults. It begins with a large pink spot, called a herald or mother patch , on the chest or back. This initial patch is often mistaken for ringworm or an insect bite. Within a week or two, other, smaller pink spots appear over the trunk, upper arms, and legs.

The spots may also occur on the neck, but they rarely spread to the face. The rash on the trunk sometimes resembles an evergreen tree with drooping branches. On individuals who are suntanned, the rash may be confined to unexposed areas of the body, such as the breasts, armpits, buttocks, and pubic area.

Diagnosis and Treatment

A dermatologist usually can diagnose the condition by examining the skin for the characteristic herald patch. She will also check the appearance of individual lesions( the lesions of pityriasis rosea typically have raised borders where scaling is most prominent) and closely examine the distribution of the rash.

If it has an unusual appearance, skin scrapings may be sent to a laboratory for analysis to rule out a fungal infection. Blood tests also may be ordered. The rash usually clears up on its own, although a physician should rule out other conditions that may cause a similar rash (such as syphilis).

Treatment includes external and internal medications for itching and inflammation. Mild inflammation and itching can be relieved with antihistamine drugs or calamine lotion, zinc oxide, or other mild lubricants or anti-itching creams. Gentle, soothing strokes should be used to apply the ointments, since vigorous rubbing may cause the lesions to spread. More severe itching and inflammation is treated with topical steroids. Moderate e...