Pityriasis Rotunda

Excerpt

Pityriasis rotunda is an uncommon acquired dermatosis related to a keratinization disorder described first in 1906 by Jean Baptiste Emil Vidal. This dermatosis was called pityriasis circinata and pseudo-ichtyose acquise en taches circulaires. Pityriasis rotunda, uncommonly encountered in some regions of the world, is not always easy to diagnose. Two variants of the condition have been identified. Type I is observed in adult Asian or Black individuals and is frequently linked to an underlying malignancy, typically stomach or hepatocellular carcinoma. Type II pityriasis rotunda manifests before age 40 and frequently has a familial pattern. This condition as not been linked to internal diseases or malignant tumors. The clinical pictures of type I and type II lesions are indistinguishable. The lesions appear as pink or light brown circular areas, finely delineated with dry scaling, and measure between 0.5 and 20 cm at their largest dimension; they typically develop on the trunk and proximal parts of the limbs. Individuals with dark skin typically exhibit hyperpigmented lesions, while those with a light complexion typically exhibit hypopigmented lesions.