Pityriasis rubra pilaris, type IV.

A 4-year-old girl presented with a 3-year history of demarcated, salmon-pink, hyperkeratotic plaques, which were symmetrically distributed on the elbows, knees, ankles, and dorsal aspects of the hands and feet. A diffuse, orange-pink palmoplantar keratoderma was also evident. Clinical and histologic findings were consistent with a diagnosis of pityriasis rubra pilaris (PRP), type IV (circumscribed juvenile). Type IV PRP develops in prepubertal children, is typically localized to the distal aspects of the extremities, and has an unpredictable course. Although ultraviolet (UV) radiation can potentially exacerbate PRP, our patient has improved with broad-band UVB phototherapy.