ULTRASOUND DESCRIPTION AND QUANTIFICATION OF IRRITANT REACTIONS INDUCED BY DITHRANOL AT DIFFERENT CONCENTRATIONS - A COMPARISON WITH VISUALASSESSMENT AND COLORIMETRIC MEASUREMENTS

Dithranol (D) is used as a therapeutic topical agent to treat psoriasi s, although it produces inflammation and staining of skin and clothing . D-induced irritation has been evaluated by visual scoring and by bio engineering techniques, evidencing modifications of the inflammatory p arameters, but no alterations of the skin barrier. The aim of our stud y was to evaluate the irritant reactions induced by D using ultrasound , and to compare the B-scanning data with visual assessments and color imetric measurements. 13 healthy women underwent 2, 3-h patch tests wi th, respectively, 0.02% and 0.1% D in white petrolatum and 1 24-h patc h test with 2% sodium lauryl sulfate (SLS). For assessing skin reactio ns, clinical judgement, colorimetry and echography were employed. Echo graphic images were evaluated by skin thickness measurements and segme ntation procedures, using an 0-30 interval, marking the hyporeflecting areas in the dermis, and a 201-255 interval, assessing the hyperrefle cting components of the image (both epidermal and dermal). In all subj ects, D produced uniform reactions, the intensity varying according to concentration. Both echographic parameters of inflammation (skin thic kness and 0-30 areas) showed an increase at all times of assessment. T he 201-255D/0-30 pixel ratio, describing the distribution of dermal ed ema, indicated that strong inflammatory reactions, such as those cause d by the application of 0.1% D, are accompanied by edema in the lower portion of the dermis. Finally, in contrast to SLS reactions, where a 24-h reduction in epidermal reflectivity was observable, D reactions a ppeared with an accentuation of the 201-255 epidermal band at 24-96-h examinations.