A common rash with some unpleasant symptoms

Pityriasis rosea is generally mild and will eventually go away

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Dr. Drew Werner
Vail CO, Colorado
May 5, 2008

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EAGLE COUNTY, Colorado — Have you had a case of the creepy crawlies? I am thinking about the kind of feeling like bugs are crawling under your skin. Have you had an itch that simply cannot be scratched? Have you had a rash that has family and friends worried you have a serious contagious disease? Read on ...

Dear Doc,
I have developed a rash that is covering my arms, legs, chest and back. It started out as a small patch and then just got worse. I was told it is Pityriasis rosea. What is it and what can I do?
— Worried in Edwards

Dear Worried,
Rashes can be miserable, although their severity may have little to do with the nature of what is the underlying cause. From mild conditions that will go away with time to a skin manifestation of a serious underlying disease, it is important to know what you have. Fortunately, Pityriasis rosea is a skin condition that is generally mild and will go away. Never the less, its appearance can be cause for concern and the severe itching can be frustrating.

Pityriasis rosea has no known cause, although an infectious etiology is suspected because the rash is much more common in the spring and fall months. While the bacteria causing the rash have not been found, the antibiotic erythromycin has been shown to lessen the duration and severity. Other experts have suspected a common virus as the cause and Valtrex, an antiviral medication, helps in some cases. Most importantly, the rash is not contagious, so staying home from work or school is not necessary.

The rash is common, typically affecting young adults in their 20s or early 30s. One study done in Singapore identified the rash in children and adults from 9 months to 82 years of age. The classic hallmark of Pityriasis rosea is the Herald Patch. This solitary ring-like lesion is usually from 1 to 4 inches in size and may appear days to weeks before the more widespread rash occurs. The Herald Patch can be easily confused with other common skin conditions, however, making early diagnosis of Pityriasis rosea difficult. There are other characteristic symptoms also commonly seen making the diagnosis easier as the full rash develops. These symptoms include:

• Red lesions
• Mild to severe itching in 25 percent of cases
• Distribution of the rash in a “Christmas Tree” pattern on the back
• Lesions have a sharp border
• Occasional scaling at the edge of the lesions

While most cases are mild, the rash of Pityriasis rosea can be severe and treatment is often needed in the form of antihistamine medications for itching, topical steroid creams and possibly oral steroids. The rash may persist for 2 to 12 weeks although once gone it rarely returns. Like many skin rashes, anything that heats up the skin may make it worse. That calls for cooler baths or showers and moderate rather than vigorous exercise. Aveeno baths may be soothing. Hot tubs should be avoided.

A variety of other skin conditions can present like Pityriasis rosea. From numular eczema, to ring worm to drug reactions and hives. While it may seem easy to tell the difference, it can be quite a challenge even for seasoned dermatologists and family doctors. When in doubt, check it out! Your doctor or primary care provider can make the diagnosis much of the time, but when all is not right, we are fortunate to have some excellent dermatologists in our valley.

In the mean time, do your best to stop scratching. Try benadryl over the counter but watch out for the drowsiness it may cause and if you are not getting better, see your doctor.

Let me know what’s on your mind at cschnell@vaildaily.com. Remember your health is your responsibility! Health is our greatest asset and it doesn’t happen by accident. If something doesn’t seem right, or questions are left unanswered don’t wait, call your doctor.