Eleven-year-old Megan was brought to the office due to a rash she had for a couple of weeks. Mom was frustrated as she put a bag of creams on the table, stating “None of these have made any difference in the rash, and it is spreading. I think she might be reacting to one of these,” she lamented.
Sensing her frustration I said, “Let’s start at the beginning with a detailed history. Megan’s rash started a little over two weeks ago as an oval red patch the size of a quarter just below her right breast. It was red and scaly, had distinct borders but was not itchy. Mom thought it might have been a form of eczema or an allergic reaction, so she applied hydrocortisone cream which did not change a thing, even after a few days.
They were at a birthday party the following Saturday. Mom mentioned it to a friend who looked at the rash and thought it might be ringworm. With that suggestion Megan’s mom was quite distressed. They went directly from the party to an urgent care center where the treating physician agreed with her friend and said it was ringworm. Mom was told to use Lotrimin, an over-the-counter anti-fungal, twice a day. They were given a prescription for a stronger anti-fungal ointment, Spectacle, to use if things didn’t improve after a week of Lotrimin.
The rash did not improve at all. After a few days mom filled the prescription for Spectacle and used it religiously. Still there was no change in the rash. The day Megan was brought in to see me she had awaken with red rash on her back and chest. This rash consisted of smaller reddish oval lesions about half an inch in size. They were scaly in the center giving them a “crinkly” appearance. There was no specific distribution to these lesions but there were far more on her back than on her chest. Now mom thought Megan maybe having an allergic reaction to the creams she was using.
After hearing the history, I had Megan sit on the examining table and take off her shirt. It was immediately apparent what she had. I smiled, finished my exam and had her get dressed and sit next to mom. I grabbed a folder that I have in each of my rooms which contains pictures and articles about various rashes. Finding the article about Pityriasis Rosea I pulled it out and laid it on the table. Mon put on her glasses and gasped. The pictures in the particular article looked exactly like Megan’s rash. She nodded in agreement, but then asked in a cautious voice…”So, what does this mean?” I assured her that this was not dangerous or serious, and went on to explain about Pityriasis Rosea (PR).
PR is a common rash that occurs in people usually between 10 and 25 years of aged. There is no known cause for it. However, it is felt to be caused by a virus. It is not contagious and typically goes away without any treatment. But it can last for 10 to 12 weeks.
PR usually starts with a solitary oval lesion called the herald or mother patch. This can be 1 to 4 inches is size and is usually located on the trunk. It is red and scaly and can look exactly like ringworm and, as in Megan’s case, is often treated as ringworm…but to no avail. After 2 to 3 weeks there is another rash that occurs on the trunk. This consists of smaller red oval lesions that are reddish or brown. They have a central scaling that gives it a crinkly appearance. There may be dozens of these lesions scattered on the back and chest. The lesions on the back follow a particular pattern in an oblique manner giving it what is described as a Christmas tree distribution. There are no creams or lotions that will shorten the course of the lesions. They do go away on their own. Some individuals may experience itching and this is best treated with an oral anti-histamine. Some patients may notice some hyper-pigmentation in the areas where the rash was, but this too should resolve with time.
Megan’s mom was relieved with the diagnosis and even more so with the prognosis. As she put her creams back in the bag she smiled and said, “Looks like I won’t be needing these anymore.” I made a copy of the article for her to share with her husband.