Medically reviewed by Dr. A.M. van Coevorden, dermatologist
Pityriasis roseaStarts with one patch, clears by itself.
Pityriasis rosea is a harmless skin condition with pink to red, lightly scaling patches, mainly on the trunk. The rash usually starts with one larger patch, the herald patch, followed within one to two weeks by smaller patches. The cause is not entirely clear; a virus probably plays a role, but the condition is barely contagious. Pityriasis rosea heals by itself, usually within six to eight weeks.
What is pityriasis rosea?
The rash follows a recognisable course. First, one round or oval, red, scaling patch of two to five centimetres appears, usually on the trunk, the neck or an upper arm or thigh: the herald patch. Within one to two weeks a more widespread rash of smaller, less vivid, oval patches with fine scaling follows. These patches lie along the lines of the skin, which often creates a pattern on the back that resembles the branches of a Christmas tree. Some people feel flu-like for a few days beforehand. The patches can itch.
The herald patch can initially resemble a fungal infection of the skin. If more oval patches appear on the trunk in the weeks after, that fits pityriasis rosea instead.
How does pityriasis rosea develop?
The precise cause is unknown. A virus probably plays a role, but unlike most viral illnesses, pityriasis rosea is barely contagious: housemates rarely catch it from each other. The condition mainly affects children, teenagers and young adults. Those who have had it almost never get it again.
What can you do yourself?
Treatment is not needed: the rash clears by itself, usually within six to eight weeks, and leaves no scars. If the itch bothers you, cooling and a neutral, soothing cream help. Shower briefly and lukewarm, use little soap and wear airy clothing; irritated skin itches more quickly. Try not to scratch, so the patches don't get damaged or inflamed.
After the rash clears, the patches can stay lighter or darker in colour for a while, especially on darker skin. That evens out by itself, usually within a summer.
When to see a dermatologist or doctor?
A doctor usually recognises pityriasis rosea immediately from the story and the picture; in case of doubt, a small piece of skin can be examined. Have your skin assessed if you are not sure it is pityriasis rosea, because other conditions can resemble it. If the itch bothers you a lot, the doctor can prescribe a cream, ointment or tablets against the itch. Further treatment is not needed: the condition heals by itself and completely.
Please note
Does the rash not clear within about three months, or does the picture not feel right to you? Have your skin assessed; what looks like pityriasis rosea can also be something else.
Frequently asked questions
Is pityriasis rosea contagious?
Barely. A virus probably plays a role, but housemates rarely catch it from each other. You don't need to avoid anyone and can simply go to school or work.
How long does pityriasis rosea last?
Usually six to eight weeks, after which the rash clears by itself and completely. For a few people it takes longer, up to several months, but that is an exception. No scars remain.
What is the herald patch?
The first, largest patch of the rash: round or oval, two to five centimetres, with scaling, usually on the trunk. Within one to two weeks the smaller patches follow, lying along the lines of the skin.
Does pityriasis rosea come back?
Almost never. Those who have had it hardly ever get it again. The patches can stay lighter or darker in colour for a while after healing; that evens out by itself.
When should you see a doctor about this rash?
If you are unsure whether it is pityriasis rosea, if the itch bothers you a lot, or if the rash has not cleared after about three months. The doctor confirms the diagnosis and can prescribe something against the itch if needed.
Sources and more information
- Pityriasis rosea (nvdv.nl)