Phototesting with a divergent UVB beam in the investigation of anti‐inflammatory effects of topically applied substances

Abstract

The divergent beam protocol can be used to demonstrate and quantify the effects of topical agents on the UVB reaction, in terms of reaction diameter, mean perfusion and changes in dose-response characteristics. The dose-response approach seems to be applicable even in diagnostic testing of an individual patient's response to UVB.

Inter‐observer variability in reading of phototest reactions with sharply or diffusely delineated borders

“…This resulted in an illuminated skin area with a diameter of 4.5 cm. Figure 1 shows the relationship between dose, LDPI‐response and visual diameter assessment as developed in reference (12).…”

“…LDPI enables a quantitative estimation of the tissue blood perfusion, by scanning a laser beam over the skin area of interest. The measurement results in a two‐dimensional data set representing the spatial variations of the skin blood perfusion (10–12, 16, 17). The instrumental settings used for this study were a scanner‐head to skin distance of 9 cm, 40 × 40 measurement sites, low resolution.…”

“…This resulted in an illuminated skin area with a diameter of 4.5 cm. Figure 1 shows the relationship between dose, LDPI-response and visual diameter assessment as developed in reference (12). Both subjects were provoked with the divergent UVB beam on five separate areas on the upper back designated A -E. Area A was illuminated using 32 s provocation time equivalent to a maximal dose of 122 mJ/cm 2 at the centre of the field.…”

“…In the divergent beam method, LDPI has been used to demonstrate skin blood perfusion by the two-dimensional mapping of the erythema, from which the MED can be calculated (11). Data can also be used to calculate a dose-response curve (12).…”

Effects of Calcipotriol Cream and Ointment, Clobetasol Cream and Ointment and Tretinoin Cream on the Erythemogenicity of UVB

“…They also showed that topical corticosteroids (betamethasone-17-valerate and betamethasone-17, 21-dipropionate), diphenhydramine hydrochloride, and indomethacin reduced UVB erythema when they were applied after irradiation. Falk et al (15) also showed that application of the topical steroid clobetasol diproprionate after UVB provocation decreased the inflammatory response. In our study, we applied topical steroid clobetasol-17-propionate cream and ointment immediately before UVB instead and showed blocking effects.…”