Pityriasis rosea (pit-uh-rahy-uh-sis row-zee-ah) is a common skin disease that causes a rash. This rash usually disappears on its own without treatment. You can expect to see the rash for about 6 to 8 weeks. Sometimes the rash lasts much longer.
Some people who develop this rash see a dermatologist to get treatment for the itch.
If this rash appears during pregnancy, a woman should tell her doctor.
Pityriasis rosea: Signs and symptoms
When people get pityriasis rosea, they often have the following signs (what you can see) and symptoms (what you feel):
- Mother patch: The first sign of this rash is a single patch on the skin. Called a "herald" or "mother" patch, this patch is the only patch on the skin for about 2 weeks. This patch can get large. It feels scaly. People who have fair to olive-colored skin will see a pink or rose-colored patch. In people who have dark skin, the color varies from violet to dark gray.
- Daughter patches: Within a week or two, more patches appear on the skin. These patches are smaller and may appear on the chest, abdomen, back, arms, and legs. Sometimes these patches develop on the neck, face, and elsewhere on the skin. Patches can even develop inside the mouth. These patches are oval shaped. If many patches appear, these new patches may form a pattern on the back. The pattern often looks like a Christmas tree.
- Patch-free zones: Patches rarely appear on the face, scalp, palms, or soles.
- Itch: The skin can itch. About half (50%) of the people have itchy skin. The itch tends to worsen when the skin gets warm, such as when a person works out or takes a hot shower.
Sometimes, a mother patch does not develop, just lots of daughter patches. Some people may get only a mother patch. It is rare for a person to get only daughter patches or a mother patch.
Some people feel poorly when they have pityriasis rosea.
Pityriasis rosea: Who gets and causes
Who gets pityriasis rosea?
People of all ages and skin colors get pityriasis rosea, but this skin disease is more likely to occur:
- Between 10 and 35 years of age.
- During pregnancy.
What causes pityriasis rosea?
No one knows what causes pityriasis rosea. Research shows that it is not an allergy. We also know that fungi (plural of fungus) and bacteria do not cause this skin disease. A virus may be the cause, but researchers have yet to prove this.
It is possible that a virus causes pityriasis rosea, but this skin disease does not seem to be contagious. It does not seem to spread from one person to another.
Pityriasis rosea: Diagnosis and treatment
How do dermatologists diagnose pityriasis rosea?
A dermatologist is usually the doctor who diagnoses pityriasis rosea. The rash is often easy for a dermatologist to recognize, but not always. In some patients, this rash can look like another skin disease. It can look like ringworm or a type of eczema called nummular dermatitis.
Sometimes a dermatologist has to order tests to make sure. A dermatologist may order blood tests or remove a bit of the skin to be certain.
How do dermatologists treat pityriasis rosea?
Pityriasis rosea usually goes away without treatment. You can expect to have the rash about 6 to 8 weeks before it disappears. Some people have it for 2 weeks. Occasionally, it lasts longer than 8 weeks.
If a patient has unbearable itching, a dermatologist may prescribe a medicine to help relieve the itch. Sometimes a dermatologist prescribes light treatments for the itch.
Outcome
The rash usually goes away on its own, leaving no trace. Some people with dark skin see flat, brown spots after the rash clears. These spots may last for months, but they eventually fade.
Most people never have another outbreak of pityriasis rosea.
Pityriasis rosea: Tips for managing
If you suspect that you have pityriasis rosacea, dermatologists recommend that you:
- Make an appointment to see a dermatologist. This way you can make sure it is pityriasis rosea, and get treatment if you have itching.
- Use lukewarm water for your showers and baths. When the skin becomes overheated, the rash can worsen and become more obvious for a while.
- Try not to get overheated. When you become overheated, the rash can worsen and become more obvious for a while.
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