What is pityriasis rotunda?
Pityriasis rotunda is a rare disease characterised by round or oval scaly, pigmented patches that mainly occur on the trunk, arms and legs. There appear to be two types of pityriasis rotunda. • Type I is seen mainly in oriental and black patients older than 60 years, and is often associated with internal disease or malignancy. • Type II occurs in patients less than 40 years, and often in several members of the same family. To date no cases of type II pityriasis rotunda have been associated with internal disease or malignancy. The appearance of lesions is the same regardless of the type of pityriasis rotunda. It is uncommon in people that have white skin. • The patches are often almost perfectly circular and sharply defined with dry ichthyosis-like scaling • The lesions range between 0.5 and 20 cm in diameter and are generally isolated, although merging of lesions can create a polycylic shape • Colours range from pink to light-brown. Lesions are usually darker than surrounding skin (hyp
