The applicability of clinical scoring systems: SCORAD and PASI in psoriasis and atopic dermatitis.

The lack of standard systems for assessment of disease severity poses a problem for the introduction of rational quality control in dermatology. The scoring systems often involve assessment of the same aspects of disease, and it may therefore be conceivable that one system could potentially be applied to routine clinical work and form the basis of disease quantification in dermatology. This study was undertaken to compare PASI (Psoriasis Area and Severity Index) and SCORAD (SCOring index of Atopic Dermatitis) scoring systems, to assess disease severity in patients with atopic dermatitis and psoriasis. Patients with psoriasis (14) and atopic dermatitis (14) were scored with both systems, and correlation coefficients and multiple regression coefficients were calculated. A significant correlation between SCORAD and PASI was found (rs = 0.66). Correlation coefficients were highest (rs = 0.87) when only atopic patients were studied, and lowest (rs = 0.57) when only psoriatic patients were studied. Assessments of area and erythema are suggested as candidates for a generalised scoring systems for dermatological disease. The results suggest that in spite of the overlap between the two score systems, significant diagnosis-specific differences exist, and neither PASI nor SCORAD is an optimal general dermatological scoring system for disease severity. Additional methodological developments are necessary.