Features ouring Pityriasis rubra pilaris over Psoriasis include following except:

Differences between Pityriasis rubra pilaris and Psoriasis Pityriasis rubra pilaris Psoriasis Age at onset Bimodal Second decade Scalp scaling Furfuraceous Adherent Keratoderma Constant less common 'Islands' of pale skin Constant Less common Nail changes No salmon patches Present Nail growth rate Moderate increase Marked increase Epidermal Kinetics Moderate increase Marked increase Munro micro-abscesses Absent Common Response to UVB Poor Good Response to coicosteroids Poor Positive Response to methotrexate Variable Good Seronegative ahropathy Rare Common