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
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PASI Score
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Extent Score
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0
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0
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0.1 to 3
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1
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3.1 to 5
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2
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5.1 to 8
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3
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8.1 to 11
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4
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11.1 to 14
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5
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14.1 to 18
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6
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18.1 to 23
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7
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23.1 to 29
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8
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29.1 to 36
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9
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36.1 to 72
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10
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The psychosocial impact is a visual analogue scale from 0 (not at all affected) to 10 (completely affected).
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Parameters for Historical Disease Severity
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Points
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individual systemic treatment, including PUVA
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1 point per treatment
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number of treatments received for more than 1 year
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1 extra point per treatment
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if total number of treatments > 200, or PUVA treatment > 1,000 J per square cm
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1 extra point
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hospital admissions for treatment of psoriasis
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1 point for every 5 admissions
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episode of erythroderma
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1 point for each episode
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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+
