An unusual cluster of circumscribed juvenile pityriasis rubra pilaris cases.

Circumscribed juvenile pityriasis rubra pilaris (PRP) is an uncommon dermatosis. We describe the unusual clustering of circumscribed juvenile PRP cases in our pediatric dermatology clinic in 2011. A retrospective chart review was done of patients presenting during the summer of 2011 with classic findings of circumscribed juvenile PRP. Clinical data including past medical and family history, presenting symptoms, infectious disease history and evaluation, biopsy results, and management were recorded. Seven patients, ages 5 to 19 years, all had strikingly similar skin findings of pink to hyperpigmented, well-defined, scaly papules and plaques on their elbows, knees, dorsal hands, ankles, and Achilles tendons. Four of the seven also had palmoplantar involvement. Four were sibling pairs and the other three were unrelated. Streptococcus pyogenes infection was suspected as a trigger in four of the patients. The unusual clustering of this uncommon disease, along with the occurrence in two sibling pairs, suggests that a genetic susceptibility unmasked by an infectious agent may play a role in its pathogenesis.