Pityriasis rubra pilaris: algorithms for diagnosis and treatment.

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease that affects men and women of all ages and also children. The clinical appearance of PRP is highly variable, as is the individual prognosis. Therefore, stratifying PRP into six disease subtypes represents a first step to personalized medicine for this rare inflammatory skin disease. The next step should be to associate specific therapeutic strategies with these subtypes of PRP. However, no randomized, controlled trials on the treatment of PRP have been performed. Consequently, the actual treatment algorithm for PRP will be based on clinical experience, small case series and case reports. The majority of published evidence is on type I PRP, whereas the treatment experience for other clinical types of PRP is still sparse and has to be gained. Nevertheless, it is now time to start developing valid algorithms as a basis for the diagnosis and treatment of PRP based on the data available. This review makes use of algorithms developed in psoriasis and atopic eczema and puts together recent insights into the pathogenesis, diagnosis and treatment experience of PRP. The innovative intention of this appraisal is to develop a structured algorithm for PRP treatment that should be further developed going forward.