Introduction: Acantholysis is rarely reported histological feature of Pityriasis rubra pilaris (PRP), recently recognized as having diagnostic specificity for differentiating PRP from psoriasis.
Case Report: Adult male patient one week after the introduction of simvastatin had experienced pruritic erythemo-squamous eruption on head and upper trunk that in a month progressed to erythrodermia, with islands of sparing. Histological picture combined pemphigus-like acantholysis with alternating hyper- and parakeratosis, follicular plugs and dermal inflammation, and confirmed the clinical diagnosis of classic adult type 1 PRP.