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Pityriasis Rosea

What is pityriasis rosea?

Pityriasis rosea is a type of skin rash. It is also called Christmas tree rash. It starts with one large round or oval scaly patch. This is called the herald patch. It then causes many more small patches. The rash most often appears on the chest, back, and belly. It can take 1 to 3 months to go away. But once it’s gone, it doesn’t come back.

What causes pityriasis rosea?

Researchers aren’t sure about the cause of pityriasis rosea. But it may be caused by a virus or bacteria. Some people may have a cold before the rash.

Who is at risk for pityriasis rosea?

The rash happens most often in people ages 10 to 35, and in pregnant women. If you are pregnant, make sure to tell your healthcare provider about your rash.

What are the symptoms of pityriasis rosea?

Symptoms can occur a bit differently in each person. In some people, the rash shows up 1 to 2 weeks after symptoms such as:

  • Headache

  • Sore throat

  • Nausea

  • Stuffy nose

  • Fever

The rash often starts with one large scaly patch in the shape of a circle or oval. This is called a herald or mother patch. The patch may be pink or red if you have pale skin. It may be purple, brown, or gray if you have darker skin. It can be 1 to 2 inches wide or larger. It usually appears on the chest or back.

Smaller patches then show up in 1 to 2 weeks on the chest, back, belly, arms, and legs. It can also show up on the neck and face. The rash can form the shape of a triangle on your back. It sometimes looks like a Christmas tree. The patches may itch, especially if your skin gets warmer during exercise or a hot shower. You may also feel tired and achy.

The symptoms of pityriasis rosea can be like other health conditions. Make sure to see your healthcare provider for a diagnosis.

How is pityriasis rosea diagnosed?

Your healthcare provider will ask about your symptoms and medical history. He or she will give you a physical exam. The physical exam will include looking closely at the rash. You may also have tests to check for other conditions that may look like pityriasis rosea. These tests may include:

  • Skin scraping. The healthcare provider scrapes the top of your skin with a small tool. The scraped tissue is examined with a microscope. This can show if the rash is from an infection. This is also done because the rash can look similar to fungal infection.

  • Skin punch biopsy. A small piece of skin is cut out and removed and sent to a lab. The skin is examined for other types of problems that may cause rash.

  • Blood tests. These are done to check for infection and other problems.

How is pityriasis rosea treated?

Treatment will depend on your symptoms, your age, and your general health. It will also depend on how severe the condition is. The rash should go away without treatment, but it can take 1 to 3 months or longer. Once the rash goes away, it doesn’t come back.

You can treat your itching with any of these:

  • Corticosteroid cream or ointment. You can put this medicine on the rash 2 to 3 times a day, for up to 3 weeks. This may help with itch, but it probably won’t make the rash disappear.

  • Calamine lotion. This is a pink, watery lotion that can help stop itching.

  • Antihistamine. This medicine can help reduce itching. You can put it on the skin as a cream or take it by mouth as a pill.

  • Other anti-itch lotion or cream. Ask your healthcare provider about other anti-itch lotion or cream that can help relieve itching. He or she may prescribe a stronger medicine if drugstore medicine isn’t helping you.

If you have severe symptoms, your healthcare provider may treat you with any of the below:

  • Prednisone. This is an oral steroid medicine. It can help ease severe itching if needed.

  • Acyclovir. This is a type of anti-virus medicine. It may help the rash go away sooner in some people if the rash is caused by a virus.

  • Ultraviolet light treatment. Exposing the skin to ultraviolet light in the first week can help lessen symptoms.

Talk with your healthcare providers about the risks, benefits, and possible side effects of all treatments.

Can pityriasis rosea be prevented?

Researchers don’t know how to prevent pityriasis rosea.

When should I call my healthcare provider?

Call the healthcare provider if you have:

  • New symptoms

  • Rash that lasts for more than 3 months

  • Symptoms that don’t get better in 1 to 2 months, or get worse

  • You have a rash and you are pregnant

Key points about pityriasis rosea

  • Pityriasis rosea is a type of skin rash. It starts with one large round or oval scaly patch. This is called the herald patch. It then causes many more small patches.

  • The rash most often appears on the chest, back, and belly.

  • Researchers aren’t sure about the cause of pityriasis rosea. But it may be caused by a virus or bacteria. Some people may have a cold before the rash.

  • The rash should go away without treatment, but it can take 1 to 3 months or longer. Once the rash goes away, it doesn’t come back.

  • You can treat your itching with cream, ointment, and oral medicine.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

Online Medical Reviewer: Kevin Berman, MD
Online Medical Reviewer: Louise Cunningham, RN
Online Medical Reviewer: Michael Lehrer, MD
Date Last Reviewed: 11/1/2018
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