A comparison of subjective and objective measures of reduction of psoriasis with the use of ultrasound, reflectance colorimetry, computerized video image analysis, and nitric oxide production.
BACKGROUND
Studies of antipsoriatic therapy often rely on subjective scoring. Objective measures have been developed but have not previously been compared with subjective scoring.


OBJECTIVE
Our purpose was to compare subjective and objective measures of reduction of psoriasis with topical therapy.


METHODS
A 2-week, double-blind, left-to-right comparative trial of betamethasone valerate against white soft paraffin was performed in 12 patients. The subjective scores were erythema, elevation, scale, and a composite total. Objective measures were nitric oxide production measured by chemiluminescence; erythema reflectance; ultrasound scan for thickness, scale, and echo-poor zone; and computerized image analysis of video images.


RESULTS
Subjective and objective measures had similar power to detect therapeutic effect. The subjective measures showed greater variation and relatively overestimated improvement. There was correlation between measures and estimates for area, redness, and thickness. Nitric oxide production was the most powerful objective measure.


CONCLUSIONS
Thickness determined by ultrasound scan and nitric oxide production are useful measures of reduction of psoriasis, which lend themselves to more powerful statistical tests than subjective interval data.
Ormerod
A D
AD
Department of Dermatology, Aberdeen Royal Infirmary, Foresterhill, Scotland, U.K.
Dwyer
C M
CM
Weller
R
R
Cox
D H
DH
Price
R
R
D000287:Administration, Topical; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage; D001624:Betamethasone Valerate / Q000008:administration & dosage; D003124:Colorimetry; D004311:Double-Blind Method; D004890:Erythema / Q000473:pathology; D005938:Glucocorticoids; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008163:Luminescent Measurements; D009569:Nitric Oxide / Q000378:metabolism; D010232:Paraffin / Q000008:administration & dosage; D011565:Psoriasis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D012680:Sensitivity and Specificity; D012867:Skin / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D014463:Ultrasonography; D014741:Video Recording
D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D009569:Nitric Oxide; D010232:Paraffin; D001624:Betamethasone Valerate