The “Herald Patch” Rash Fall/ Winter Newsletter 2016
Pityriasis rosea (PR) is a fairly common rash that typically occurs during the fall and spring, but can develop any time during the year. It most frequently appears in children and teenagers, however, those in other age groups can develop PR as well. The rash is characterized by pink or salmon colored, scaly, oval and circular shaped patches. The scale is fine and subtle as opposed to other rashes like psoriasis where the scale is bigger and more noticeable. Unique to PR is something called the “herald patch”; this means that patients often notice the appearance of one larger pink patch, the “herald patch”, and then several days or even 1-2 weeks later they develop many smaller similar appearing patches. If you pinch your skin the creases will go in one certain direction, which is usually the same as the orientation of the longer side of the oval. PR most commonly appears on the trunk, upper arms and upper legs, with more scattered patches elsewhere; however, just like with most rashes, there are a number of different presentations of PR that can make diagnosing it trickier. Sometimes PR develops little blisters, sometimes it develops bruise like areas called purpura or sometimes PR is isolated to intertriginous areas such as the armpits. Interestingly, PR is usually not itchy or bothersome to patients, except for the actual presence of the rash. Most people otherwise feel well when they have PR, but on a rare occasion a patient may report an associated fever, headache, achiness or tiredness. The rash usually lasts 6-8 weeks and then spontaneously resolves. Unusually, it can persist longer, even for many months. When it heals there can be residual light white areas where the rash was previously, but these improve and resolve with time. The cause of PR is unknown. It is possibly caused by a viral infection, but the exact cause remains unknown. Often no treatment is required for PR since it is usually not itchy and it does not indicate any serious underlying illness; in addition, it resolves on its own, but most of the time we will prescribe a cortisone cream to enable it to go away faster.