Modified Psoriasis Area and Severity Index (mPASI)
The severity of the psoriatic lesions on the arms and legs was recorded for redness, thickness, and scaliness (Table 3). For each clinical sign, a single score reflected the average severity of all psoriatic lesions on the arms or the legs.
The extent of psoriatic involvement was recorded for the arms and legs using the following scale:
Calculation of mPASI score
Redness, thickness, and scaling were all graded according to the scale 0 = none; 1 = mild; 2 = moderate; 3 = severe; 4 = very severe. The weighting factor for the arms was 20% (0.2) and for the legs was 40% (0.4). In all cases the median number of handprints per arm and per leg was 1. The extent of involvement was 0% to 10%, so the area score was 1 in all cases. An example is shown below.
Local Skin Reaction (LSR) Assessment With Visual Analog Scale (VAS)
The LSR involved signs assessed by the investigator and symptoms reported by the subject. The investigator assessed the treatment and immediate surrounding areas for perilesional erosion/ulceration, vesicles, erythema, scaling, edema, and atrophy. The most severe intensity of each LSR category was graded according to the scale in Table 4. The subjects assessed burning and pain after application.
Itch by Numerical Rating Scale (NRS)
The intensity of psoriatic itch within the previous 24 hours was graded by the subject according to a 10-point numerical rating scale (NRS) in which 0 = no itch at all and 10 = the worst itch one can imagine.
Statistics
Since much of the data consisted of small whole numbers, data were analyzed using non-parametric statistics with P=0.05 as the cutoff value for significance. Differences were evaluated for significance by the Wilcoxon Signed Rank test.
The severity of the psoriatic lesions on the arms and legs was recorded for redness, thickness, and scaliness (Table 3). For each clinical sign, a single score reflected the average severity of all psoriatic lesions on the arms or the legs.
The extent of psoriatic involvement was recorded for the arms and legs using the following scale:
Calculation of mPASI score
Redness, thickness, and scaling were all graded according to the scale 0 = none; 1 = mild; 2 = moderate; 3 = severe; 4 = very severe. The weighting factor for the arms was 20% (0.2) and for the legs was 40% (0.4). In all cases the median number of handprints per arm and per leg was 1. The extent of involvement was 0% to 10%, so the area score was 1 in all cases. An example is shown below.
Local Skin Reaction (LSR) Assessment With Visual Analog Scale (VAS)
The LSR involved signs assessed by the investigator and symptoms reported by the subject. The investigator assessed the treatment and immediate surrounding areas for perilesional erosion/ulceration, vesicles, erythema, scaling, edema, and atrophy. The most severe intensity of each LSR category was graded according to the scale in Table 4. The subjects assessed burning and pain after application.
Itch by Numerical Rating Scale (NRS)
The intensity of psoriatic itch within the previous 24 hours was graded by the subject according to a 10-point numerical rating scale (NRS) in which 0 = no itch at all and 10 = the worst itch one can imagine.
Statistics
Since much of the data consisted of small whole numbers, data were analyzed using non-parametric statistics with P=0.05 as the cutoff value for significance. Differences were evaluated for significance by the Wilcoxon Signed Rank test.
RESULTS
Twelve subjects (80%) completed the study. One subject withdrew because of a change in work schedule that interfered with study visits. Two other subjects were lost to follow-up.
Body Surface Area
The median BSA at baseline (n=15) was 2.00, ranging from 2.0 to 4.0. At the end of the study (n=12), the median BSA was 2.25 and values ranged from 2.0 to 4.0. The median BSA at the end of study did not differ significantly from baseline.
mPASI Scores
The median mPASI scores of the arms and legs are shown in Tables 5 and 6. Differences between the 650-microsecond and excimer lasers were not significant for redness, thickness, scaliness, mPASI scores for arms and legs, and mPASI scores. Overall mPASI scores for 650-microsecond vs. excimer lasers throughout the study period are shown in the Figure 1. Values decreased rapidly until visit 10 when they leveled off at 1.3 and decreased to 1.2 at the end of the study.
Body Surface Area
The median BSA at baseline (n=15) was 2.00, ranging from 2.0 to 4.0. At the end of the study (n=12), the median BSA was 2.25 and values ranged from 2.0 to 4.0. The median BSA at the end of study did not differ significantly from baseline.
mPASI Scores
The median mPASI scores of the arms and legs are shown in Tables 5 and 6. Differences between the 650-microsecond and excimer lasers were not significant for redness, thickness, scaliness, mPASI scores for arms and legs, and mPASI scores. Overall mPASI scores for 650-microsecond vs. excimer lasers throughout the study period are shown in the Figure 1. Values decreased rapidly until visit 10 when they leveled off at 1.3 and decreased to 1.2 at the end of the study.
