Author: Vanessa Ngan, Staff Writer, 2005.
Pityriasis rotunda is also known as ‘pityriasis circinata’ and ‘acquired pseudo-ichthyosis’.
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.
The appearance of lesions is the same regardless of the type of pityriasis rotunda. It is uncommon in people that have white skin.
Once lesions develop they usually remain unchanged throughout life unless the underlying internal disease or malignancy is treated, in which case they resolve or improve.
The cause of pityriasis rotunda is unknown but it may be a variant of ichthyosis vulgaris. Type I pityriasis rotunda (paraneoplastic pityriasis rotunda) most often occurs with liver and stomach cancer. Other conditions that type I pityriasis rotunda has been associated with include:
Patients with pityriasis rotunda need to undergo medical and physical examinations and appropriate laboratory and radiographic tests to check for internal disease or malignancies.
There is no specific treatment for pityriasis rotunda. Lesions usually improve or resolve with treatment of the underlying internal disease or malignancy. Symptomatic treatment of lesions using topical retinoids, salicylic acid ointment, and lactic acid lotion has been used.
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