Pityriasis rosea. Pityriasis rosea is an exanthema most likely caused by a virus. The "herald patch" seen in the upper arm appeared a couple of weeks before the spread of the eruption. The herald patch with its collarette scaling may resemble ringworm of the body. The longer axis of the ellipsoid lesions on the trunk follows the direction of the ribs.
Picture: Raimo Suhonen
Primary/Secondary Keywords