What is pityriasis rosea?
Pityriasis rosea is a type of skin rash. It is also called Christmas tree rash. It starts with 1 large, scaly patch. It may be round or oval. 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.
How to say it
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 people. 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:
- Sore throat
- Stuffy nose
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 often 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 diagonal stripes down your back like the branches of 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.
Some of these symptoms can be caused by 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 health history. They 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 a lot like a fungal infection.
- Skin 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 a 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 likely 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 lotions or creams that can help ease itching. They may prescribe a stronger medicine if an over-the-counter medicine isn’t helping you.
No treatment has been shown to be reliably effective. But if you have severe symptoms, your healthcare provider may try to treat you with any of the below:
- Prednisone. This is a steroid medicine taken by mouth (oral). 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 in spite of using suggested treatments
- You have a rash and you are pregnant
Key points about pityriasis rosea
- Pityriasis rosea is a type of skin rash. It starts with 1 large, scaly patch. It may be round or oval. 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 medicine taken by mouth (oral).
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.