Pityriasis rosea: This common skin disease causes patches on the skin. Your dermatologist may call the large patch a mother patch. The smaller patches are daughter patches.
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.
This rash can be very itchy.
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: Diagnosis, treatment, and outcome
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.
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.