Psoriatic onycho-pachydermo periostitis.

A 46-year-old woman presented with onycholysis and swollen, painful digits. No other stigmata of psoriasis were present. Magnetic resonance imaging of the hands showed an extensive periosteal reaction of the phalangeal tuft. Psoriatic onycho-pachydermo periostitis (POPP) is a rare subset of psoriatic arthritis that is characterized by psoriatic onychodystrophy, connective-tissue thickening above the distal phalanx, and a periosteal reaction. Treatment of POPP is difficult; however, low-dose methotrexate and anti-TNF-alpha agents may be beneficial. In patients who are unresponsive or intolerant of these medications, other biologic and non-biologic disease modifying anti-rheumatic drugs need to be considered.