ABSTRACT
The Self-Administered Psoriasis Area and Severity Index (SAPASI) provides patients with a means to objectively measure the severity of their psoriasis. The measure takes into account the area of psoriasis lesions on the body and the characteristics of these lesions-the redness, thickness and scaliness of the lesions. Subjects shade in on a silhouette the areas which are involved. The subjects also make a mark on each of three lines to designate the redness, thickness and scaliness of the lesions. To score the instrument, the rater first scores the area involved for each of four areas: head, upper extremities, trunk and lower extremities. The scoring is done on a 0 to 6 scale, where 0 indicates no involvement, 1 is <10%, 2 is 11-30%, 3 is 31-50%, 4 is 51-70%, 5 is 71-90%, and 6 is 91-100%. Each of the four area scores is multiplied by a constant indicative of how large that body region is. The head area is multiplied by 0.1, the upper extremity area by 0.2, the trunk area by 0.3, and the lower extremity area by 0.4. These normalized area scores are then summed to yield a total area score. The color, thickness and scale are scored by measuring in millimeters the length of the line from its beginning to the mark made by the subject. These lengths are then summed, and divided by the total length of the line in millimeters. This is multiplied by four to normalize each of the length scores to a 0-4 scale. Multiplying the result by the total area score yields the final SAPASI score. To use the Scoring Sheet:
(1) The identifying information is completed. (2) The area scores for head, upper extremity, trunk and lower extremity are placed in column 1, rows 1 through 4. The area scores
are estimated using the table in the upper left-hand corner of the scoring sheet. (3) The area scores are multiplied by the corresponding values in column 2 and placed in column 3. (4) A total area score is obtained by summing the values in column 3 and placing this in row 5. (5) The color, thickness and scaliness measurements are placed in lines 6, 7 and 8. The sum of these is placed in line 9. (6) The length of the visual analog scale is measured and placed in line 10. (7) Line 9 is divided by line 10 and placed in line 11. (8) Line 11 is multiplied by 4 and placed in line 12. (9) Line 12 is multiplied by the total area score from line 5. The result, the SAPASI score is placed in line 14.
