Psoriatic Onycho-Pachydermo-Periostitis

Abstract

Joint and nail involvement in psoriasis is relatively common. In contrast, bony involvement of the terminal phalanx under a psoriatic nail is rare. We report on this psoriatic onycho-pachydermo-periostitis and suggest pathophysiologic mechanisms. Two new cases are reported and the data are compared with the data from eight similar cases reported in the literature. All subjects presented with similar changes--onychopathy, soft-tissue thickening, and radiologic features consisting of bone erosions and a periosteal reaction of the terminal phalanx. Of the 10 patients, two had no history of psoriasis before a diagnosis of psoriatic onycho-pachydermoperiostitis was made. The inflammation is likely transmitted from the psoriatic nail to the adjacent underlying bone by the same mechanism as in enthesopathies. Psoriatic onycho-pachydermo-periostitis should be recognized as a specific entity in the spectrum of psoriatic disease.