Salford Psoriasis Index (SPI)

This score is a composite tool and is not called a quality of life score; however, it does include consideration of the psychological impact. The index is divided into three sections. Firstly, the Psoriasis Area Severity Index (PASI) is completed (see Assessment and planning care). Once a score is reached, it is then given a SPI score as per Table 6.4. Secondly, the psychological impact is measured by asking the patient to mark on a visual analogue score. The patient is asked ‘about the extent to which they perceive that their psoriasis is affecting their day-to-day life at the time of the assessment’. The score is from 0 to 10 with 0 being not at all affected and 10 being completely affected (Kirby et al., 2000). The third and final section of the Index is calculated according to how much treatment the patient has undergone (see Box 6.7).

Table 6.4 SPI scores in relation to PASI scores.   PASI SPI extent   0 0   0.1–3 1   3.1–5 2   5.1–8 3   8.1–11 4   11.1–14 5   14.1–18 6   18.1–23 7   23.1–29 8   29.1–36 9   36+ 10

Box 6.7 Points for the amount of treatment received 1 point for each individual systemic treatment including PUVA (Psoralen plus ultraviolet light A). 1 extra point for each treatment received for > one year. 1 extra point if patient has received > 200 treatments or > 1000J/cm2 of PUVA. 1 point for every hospital admission for the treatment of psoriasis. 1 point for every episode of erythema.

Once each individual score has been calculated, the total score is then expressed as a ratio. The first number represents the SPI, the second psychological impact and the third the amount of treatment received. Therefore, a ratio of 1:1:0 shows that the individual has very little psoriasis, which is having a minimal psychological impact with no systemic treatment or hospital admissions. A ratio of 10:10:6 shows very severe psoriasis which is having a major psychological impact and there is a significant history of systemic treatments and/or hospital admissions.