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Pityriasis Rosea - Topic Overview


How is pityriasis rosea diagnosed?

Your doctor will diagnose pityriasis rosea by looking at the rash. Diagnosis can be hard when only the herald patch is visible, because the condition is often mistaken for ringworm or eczema at this time. After the rash appears, diagnosis is generally clear.

If the diagnosis is unclear, your doctor may do a potassium hydroxide (KOH) test to make sure the rash is not caused by a fungal infection. A skin sample may be taken from the infected area and examined under the microscope (biopsy). If the diagnosis is unclear in a sexually active person, a test for syphilis is often done.

How is it treated?

Pityriasis rosea goes away without treatment. It usually lasts about 6 to 8 weeks. If the rash itches, you may wish to use skin lotions and lubricants to soothe itching. If symptoms are severe, your doctor may prescribe anti-inflammatory medicines such as corticosteroids to relieve itching and reduce the rash.

Although treatment isn't needed, antiviral medicines like acyclovir may shorten the time you have the rash, especially if you take them when the rash first starts.

Exposing the rash to sunlight may make it go away more quickly. But exposing your skin to the sun too long can result in sunburn and increase your risk of skin cancer.

If the rash lasts more than 3 months, contact your doctor.

To relieve itching at home:

  • Try to stay cool. Getting too warm and sweaty can make the rash and itching worse.
  • Avoid taking hot showers or baths. Keep the water as cool as you can tolerate.
  • Add a handful of oatmeal (ground to a powder) to your bath. Or you can try an oatmeal bath product, such as Aveeno.
  • Try an over-the-counter 1% hydrocortisone cream for small itchy areas. Use the cream very sparingly on the face or genitals. Note: Do not use the cream on children younger than age 2 unless your doctor tells you to. Do not use in the rectal or vaginal area in children younger than age 12 unless your doctor tells you to.
  • Try an over-the-counter antihistamine, such as chlorpheniramine maleate (Chlor-Trimeton) or diphenhydramine (Benadryl). Don't give antihistamines to your child unless you've checked with the doctor first.
  • Apply a moisturizer or calamine lotion to the skin while it is damp.
  • Use as little soap as possible. Use gentle soaps, such as Basis, Cetaphil, or Dove. Avoid deodorant soaps when you have a rash.
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WebMD Medical Reference from Healthwise

Last Updated: August 14, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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