In one review of 64 cases, all patients were undergoing assessment for an underlying medical condition and the lesions of PR were noted incidentally. Few could remember the duration of the lesions, which varied from 1 week to 2 years. They range from 0.5-20 cm in size and generally are isolated, but merging of lesions will result in a polycyclic configuration. Several lesions usually are present, ranging from 4-80. One patient had over 100 lesions.
Lesions usually are present on the trunk, buttocks, and upper and lower extremities.
Some authors believe it is a variant of ichthyosis vulgaris because both have similar histologic findings. Some authors believe PR is caused by undernutrition, but this is not universally accepted. In familial cases, an autosomal dominant mode of transmission has been proposed. The presence of systemic disease appears to be common in black South African and Japanese patients, but is much less likely among Caucasian patients. Osteitis Chronic diarrhea Scleroderma Resolution of PR has been noted with treatment of the underlying malignancy.