Background: Psoriatic onycho-pachydermo-periostitis (POPP) is a rare manifestationof psoriatic arthritis that is often misdiagnosed as a nail infection. The treatment for POPP has notyet been established. Case Report: We present a case of a 67-year-old man who had no psoriatic skin lesionswith POPP, characterized by psoriatic nail changes, painful swelling of the distal soft tissues on thegreat toes and fingers, and enthesopathies of the involved terminal phalanges. The clinical nail andarthritic changes were improved with methotrexate treatment 4 mg weekly for 6 months. Conclusions: Methotrexatecan be recommended as the first-choice therapeutic agent for patients with POPP.

Keywords: Anti-Inflammatory Agents, Non-Steroidal - therapeutic use, Arthritis, Psoriatic - pathology, Methotrexate - therapeutic use, Nail Diseases - pathology, Periostitis - pathology