RESUMEN
Psoriasis is a chronic skin disorder involving many parts of the body including skin, nails and joints with severe negative effects on patient's quality of life. Nail involvement is one of the most difficult involvements of this disease to treat. Psoriatic arthritis categorized in sero-negative spondilo-arthropaties with some deforming characteristics. The aim of the present study was to evaluate the relationship between psoriatic arthritis and nail involvement based on standard psoriatic nail involvement score [NAPSI]. Psoriatic patients visiting dermatology clinic of Razi hospital were selected. Patients with arthritis enrolled as the case group while patients that had no joint involvement participated in control group. After matching, demographic data of both groups as well as NAPSI score and nail involvement characteristics collected through special questionnaires and analyzed with SPSS version 14. A total of 30 patients with psoriatic arthritis and 75 patients without arthritis were enrolled the study. Analysis of collected data demonstrated that nail involvement among patients with psoriatic arthritis [mean NAPSI score=46] was more common and severe than patients without joint involvement [mean NAPSI score=9.23] [P<0.05]. It seems that there is a significant difference between psoriatic patients presenting with or without arthritis and presence of arthritis probably can determine occurrence and extension of nail involvement