Severity tools

Tools to assess disease severity are important both in skin assessment and the evaluation of treatment effectiveness. Developed tools are now widely used for common chronic inflammatory skin conditions such as eczema and psoriasis. It is important to try to use valid and reliable standardised tools to ensure rigorous measurement. Valid tools measure what they are intended to measure and reliable tools ensure that the measure gained under the same conditions (such as degree of severity) is derived consistently. In addition, it is necessary to practise and develop skill in using some tools, for example the assessment of a PASI score to ensure reliability of assessment across observers and by the same clinician, under the similar clinical conditions. Details of commonly accepted valid tools are outlined in Table 3.7; copies of the PASI and SCORAD tools are reproduced in the Appendices 1 and 2 respectively. Acne severity is a core complex area for scoring; a recent review paper identified as many as 25 scales for the global assessment of acne, which indicates the lack of consensus on the issue and a gold standard (Lehmann et al., 2002).

Table 3.7 Common chronic skin severity tools.   Tool   Disease parameters   Source material   PASI: Psoriasis Area Severity Index   This is the most widely used tool to assess psoriasis disease severity. The estimate is based on the percentage area affected of four body regions - head, trunk, upper and lower extremities - which is given a value of 0 (no psoriasis) to 6 (>90% present). The following clinical parameters are also used within a 0-4 scale - ranging from no symptoms to very marked symptoms, again for the different body areas. 1. Erythema (redness) 2. Induration (thickness) 3. Scaling (flaking or desquamation) 4. BSA affected A formula is used to calculate the PASI score. PASI scores: 1–10: mild to moderate; 11–20: moderate to severe and >20 severe; the theoretical maximum score being 72 (see Appendix 1).   Ashcroft et al. (1999); Ramsay and Lawrence (1991); Exum et al. (1996)   SCORAD Index   The European Task Force on Atopic Dermatitis has developed the SCORAD (SCORing AD) index to create a consensus on assessment methods for AD. 1. Objective items: a. Extent: Apply the rule of nines (see BSA given earlier) graded 0–100 on the front/back drawing. b. Intensity: consists of 6 items – erythema, oedema, excoriations, lichenification, oozing/crusts and dryness. Each item can be graded on a scale 0–3. 2. Subjective items include: a. Daily pruritus b. Sleeplessness Both subjective items can be graded on a 10-cm visual analogue scale. SCORAD scores: The maximum SCORAD score is 103. The maximum subjective score is 20. The maximum objective SCORAD score is 83 (plus an additional 10 bonus points). Bonus points are given for severe disfiguring eczema (on face and hands). Mild <25, mild to moderate 25–50 and severe >50. There are criticisms of the tool including that it can be time consuming in clinical practice and that it has a bias for use with children (see Appendix 2).   Kunz et al. (1997); Oranje et al. (2007); https://adserver.sante.univ-nantes.fr/Scorad.html   (Revised) Leeds Acne Score (1998)   Pictorial grading system – a photographic assessment system with severity criteria as: 1. Extent of inflammation 2. Range and size of inflamed lesions 3. Associated erythema Overall assessment is based predominantly on the number of inflamed lesions and their inflammatory intensity. The published photos demonstrate the extensive range of facial acne grades of increasing severity from 1 (least severe) to 12 (most severe). Different parts of the body are used, such as face, chest and back. The system is not suitable for those with non-inflamed acne or with highly localised acne or those with sporadic and asymmetrical large nodular lesions. Most patients have a combination of inflamed and non-inflamed lesions; the grading system focuses on inflamed lesions.   O’Brien et al. (1998) which builds on Burke and Cunliffe (1984)