The biopsy specimen revealed regular psoriasiform epidermal hyperplasia. The granular layer was diminished, and confluent parakeratosis was present in the stratum corneum. An inflammatory cell infiltrate, composed of lymphocytes, histiocytes, and neutrophils, was observed around the vessels of the superficial plexus. Also, spongiform pustules were present within the epidermis.
Psoriasis is a multifactorial disease with an uncertain etiology. The pathogenesis of the disease seems to involve both environmental and genetic factors.1 Yet, the striking symmetry of psoriatic plaque distribution and the widely recognized role of psychological stress in triggering worsening psoriatic symptoms have fueled research into the neuropathogenesis and neuropharmacology of psoriasis.2