Pityriasis rosea

What it is

Pityriasis rosea is a rash occurring on the skin which can last for several weeks. It usually occurs in children and young adults. It often begins as a single large scaly oval patch on the chest or back, called the herald or mother patch. Within a week or two, multiple pink oval patches appear on the body, arms, thighs and sometimes on the neck. These spots are smaller than the herald patch, and over the back they often form a pattern resembling the outline of an evergreen tree with drooping branches. The rash causes no symptoms, or mild itching.

What causes it

The cause is unknown. It is not caused by a fungal or bacterial infection. It is neither an allergic reaction nor a sign of any internal disease. A virus has been suggested, based on the fact that the disease occurs only once, starts suddenly and often settles by itself, but this theory has not been proven. It does not spread from person to person.

How we treat it

Pityriasis rosea is a self-limiting disorder, but it may take as long as six to eight weeks — nearly two months — to settle, so you need a lot of patience. Your dermatologist may prescribe soothing lotions, emollients and antihistamines for the itching. Topical steroids may be required. Ultraviolet light treatment under supervision may be helpful.

What you can do

You can continue all normal activities, including going to school or work. You can bathe, use soap and eat a normal diet.

“Be reassured that it is a common and harmless disorder.” — Dr. D. A. Satish, patient leaflet