Antipsoriatic effect of local corticosteroids--O2-consumption and blood flow measurements compared to clinical parameters.

Ten patients with chronic plaque-type psoriasis were treated topically with the group IV corticosteroid clobetasol propionate cream (Dermovate) with and without occlusion with a semipermeable hydrocolloid dressing (Comfeel Coloplast, Denmark). The effect of treatment was compared with untreated skin and evaluated in terms of (a) O2-consumption as measured by the TCM-2-oxygen monitor from Radiometer, Denmark, (b) blood flow as measured by a laser-Doppler flowmeter (Perimed, Sweden), (c) temperature measurements using thermo-couples and (d) a clinical score. While steroid + occlusion had a very pronounced effect measured by all parameters and apparent after 24 h, the steroid alone was only marginally effective after 7 days. No placebo effect was detectable in untreated skin with the laboratory methods used. It is suggested that the methods described can be used to evaluate other treatment schedules. Recently it has been shown that measurement of oxygen consumption by transcutaneous O2 electrodes might reflect disease activity in psoriatic plaques. Transcutaneous O2 decreases when a tourniquet is applied around the extremity investigated and the decrease per minute has been used as a measure of the metabolism of normal and psoriatic skin. In a later study it was shown that stripping of the skin prior to measuring was essential as a diffusion barrier was present in the horny layer. It has been previously shown that occlusion of an area to which corticosteroid has been applied increases absorption as estimated by the intensity of blanching. In the present study the effect of occlusion and non-occlusion of corticosteroid treated sites in psoriasis has been compared using clinical and laboratory parameters.