Interaction of commonly used emollients with photochemotherapy

Even though emollients are commonly used in combination with photochemotherapy, we still lack guidance for the selection of the appropriate emollient to be used in combination with photochemotherapy. The purpose of our study was to determine the interaction of commonly used emollients with photochemotherapy.

The study was carried on 75 healthy volunteers. In order to assess the effects of five different emollients--white petrolatum, 3% salicylic acid in white petrolatum, Balmandol, Decubal and Urederm hydro--the subjects were divided into five groups. Minimal phototoxic dose (MPD) was determined by irradiating two rows of six circular test fields on the back of the subjects with increasing doses of UVA. One of the emollients listed above was applied to the skin under the upper rows alternatively, whereas the lower rows served as control.

Application of Urederm hydro and Decubal before exposure to UVA resulted in a statistically significant decrease in the MPD in all subjects. Even though application of white petrolatum and white petrolatum containing 3% salicylic acid decreased the MPD in most of the subjects and Balmandol application slightly increased the MPD, the results did not reach statistical significance.

According to our findings, it is probable that the total dose of UVA needed to cause clearing of psoriasis would be decreased by application of Urederm hydro and Decubal prior to photochemotherapy. We noted a slight photoprotective effect of Balmandol in the UVA range, but this finding has to be further studied. Clinical studies are needed to clarify the effects of these emollients on the course and outcome of photochemotherapy.