Affected individuals usually have several lesions, ranging from 4 to 80, that are commonly found on the buttocks, thighs, abdomen, trunk, and upper and lower extremities. 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. Colors range from pink to light-brown. Once the lesions develop, they usually remain unchanged throughout life unless the underlying internal disease or malignancy is treated, in which case, they resolve or improve.There appear to be two types of pityriasis rotunda. Type 1 pityriasis rotunda usually affects South African and East/Southeast Asian individuals older than 60 years who tend to have associated malignancies (cancers) or systemic disease. The lesions found in those with type 1 are usually darker (hyperpigmented) than the surrounding skin; and other family members are not affected. Type 2 affects people with lighter skin who are younger than 40 years. These individuals do not have any associated malignancy or systemic diseases, but have multiple lesions that are lighter (hypopigmented) than the surrounding skin. Type 2 also tends to run in families.
- Rao J. Pityriasis rotunda. eMedicine. March 2009; http://emedicine.medscape.com/article/1107624-overview#showall. Accessed 1/18/2012.
- Pityriasis rotunda . DermNet NZ. July 2011; http://dermnetnz.org/scaly/pityriasis-rotunda.html. Accessed 1/17/2012.