The Salford Psoriasis Index (SPI) is a simple scoring system for psoriasis that measures current extent, psychosocial disability and past severity of the disease. It is intended to give a better understanding of an individual's experience and needs. The authors are from the University of Manchester in Salford, England.
Component Scores:
(1) extent score, based on the PASI
(2) psychosocial impact, as measured by a 10-point visual analogue scale
(3) historical disease severity score
PASI Score
|
Extent Score
|
0
|
0
|
0.1 to 3
|
1
|
3.1 to 5
|
2
|
5.1 to 8
|
3
|
8.1 to 11
|
4
|
11.1 to 14
|
5
|
14.1 to 18
|
6
|
18.1 to 23
|
7
|
23.1 to 29
|
8
|
29.1 to 36
|
9
|
36.1 to 72
|
10
|
The psychosocial impact is a visual analogue scale from 0 (not at all affected) to 10 (completely affected).
Parameters for Historical Disease Severity
|
Points
|
individual systemic treatment, including PUVA
|
1 point per treatment
|
number of treatments received for more than 1 year
|
1 extra point per treatment
|
if total number of treatments > 200, or PUVA treatment > 1,000 J per square cm
|
1 extra point
|
hospital admissions for treatment of psoriasis
|
1 point for every 5 admissions
|
episode of erythroderma
|
1 point for each episode
|
where:
• The points for total treatment does not appear to combine the total number and the amount of PUVA treatment.
• The points for hospital admissions seems to be an integer assigned after each 5 hospital increment.
• Since so much therapy has been switched to outpatient, hospital admissions may not be a sensitive measure.
historical disease severity score =
= SUM(points for all 6 parameters)
Interpretation:
• The index is reported as extent score : impact score : historical disease severity score (for example, 2 : 3 : 1)
• minimal disease would have an index of 1 : 1 : 0
• severe, chronic, and debilitating, disease would have an index of 10 : 10 : 100+