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Pityriasis rosea

PITYRIASIS ROSEA

What are the aims of this leaflet?

This leaflet has been written to help you understand more about pityriasis rosea. It tells you what it is, what causes it, what can be done about it, and where you can find out more about it.

What is pityriasis rosea?

Pityriasis rosea is a common rash that is usually mild and lasts about 6 to 8 weeks. Its name means that the rash has a fine scale (pityriasis) and it tends to be pink (rosea).

What causes it?

The cause of pityriasis rosea is still not known. It is thought to be triggered by a virus as it occurs in clusters (in schools, army barracks, families, etc) and is more frequent in the winter. However, the risk of passing it on to anyone else is very low. It is most common between the ages of 10 and 35 years.

Is pityriasis rosea hereditary?

No.

What are its symptoms?

People with pityriasis rosea usually feel fine, though they may be slightly unwell just before the rash starts, with a mild headache, and the rash can be itchy or uncomfortable.

What does pityriasis rosea look like?

The first sign of pityriasis rosea is a single scaly pink patch, which is known as a ‘herald patch&rsquo because it comes up a few days or weeks before the rash spreads. The herald patch is usually a single round or oval patch on the torso. It is usually larger than patches that come up later and can be confused with a patch of ringworm (tinea). A week or two later, a more widespread scaly patchy rash usually appears on the body in a pattern resembling the branches of a Christmas tree. These patches appear in crops, then slowly fade over the next 6-8 weeks. It is unusual for the rash to affect the hands, feet or face. In people who have dark skin, the patches may leave areas of darkness or lighter pigmentation for several months. It does not leave scars.

How will it be diagnosed?

There is no diagnostic test for pityriasis rosea, but the story of a herald patch followed by a more widespread scaly rash is usually enough for your doctor to make the diagnosis. If there is any doubt, or the rash lasts longer than two months, your doctor may recommend a skin biopsy (skin sample taken after local anaesthesia) for laboratory analysis or blood tests to rule out other rashes that can look like pityriasis rosea. The herald patch can resemble ringworm, which can be ruled out if needed by sending a skin scraping sample for laboratory fungal tests.

Can it be cured?

Pityriasis rosea clears up by itself within a few months. There is no specific treatment..

How can it be treated?

Most people do not need any treatment. If your skin is itchy or sore, a moisturiser may help. Avoid washing the affected area with soap or shower gels as this can cause more dryness – use a soap substitute instead. Antihistamine tablets may also help and can be bought without prescription. If the rash is still uncomfortable, a mild steroid cream such as hydrocortisone cream can be applied twice a day. If the itch is still severe despite these treatments, your doctor may suggest a stronger steroid cream or treatment with ultraviolet light.

What can I do?

  • There is no need to treat the rash if it is not causing any symptoms.

  • If the rash does not clear up after 3 months, consult your general practitioner again.

  • There is no reason to keep children with pityriasis rosea away from school.

Where can I get more information about it?

Web links to detailed articles and leaflets:

www.aad.org/pamphlets/pityrias.html

http://www.dermnetnz.org/viral/pityriasis-rosea.html

http://www.patient.co.uk/health/pityriasis-rosea-leaflet

For details of source materials used please contact the Clinical Standards Unit (clinicalstandards@bad.org.uk).

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS

PATIENT INFORMATION LEAFLET

PRODUCED MAY 2008

UPDATED AUGUST 2011, NOVEMBER 2014

REVIEW DATE NOVEMBER 2017

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