Abstract

OBJECTIVE: To test the hypothesis that pustulosis palmaris et plantaris and psoriatic arthritis (PsA) are two distinct diseases, and that the associated dermatoses are therefore also distinct diseases. METHODS: We prospectively performed clinical, radiological, biological, and bone scan investigations in 23 outpatients with pustolotic arthritis and 23 outpatients with PsA, matched by gender, age (+/- one year) and duration of arthritis (+/- two years). RESULTS: The anterior chest wall, especially the sternocostoclavicular joints, was more frequently involved in pustulotic arthritis than in PsA, both clinically (82% v 43%; p < 0.001) and radiologically (47% v 17%; p < 0.05). Sternocostoclavicular joints generally presented with erosive lesions in PsA, and with large ossifications in pustulotic arthritis. Peripheral joint involvement was mono- or oligoarticular, affecting proximal joints, in pustulotic arthritis (74% v 21%; p < 0.01), and polyarticular, involving small distal joints, in PsA (60% v 0%; p < 10(-4)), in which condition it was also more often erosive (43% v 8%; p < 0.01). The frequency of sacroiliitis and of spine involvement was similar in pustulotic arthritis and PsA. Biology and bone scan did not help distinguish between the two groups. CONCLUSIONS: Pustulotic arthritis and PsA are clinically and radiologically different, therefore pustulosis palmaris et plantaris and psoriasis are most probably distinct dermatological diseases.