Pityriasis, or pityriasis rosea Gibert, is a relatively harmless skin disease, of which the cause is yet unknown. The first symptom is the appearance of a pink or brown oval patch, in most cases on the thorax, with desquamation (peeling) observed on the surrounding skin. These patches can be up to several centimeters in diameter. Similar but much smaller patches also appear, covering the torso or extremities. There is no itching associated with this condition, and no treatment is required, as pityriasis rosea heals itself after a few weeks.