Emollients and Photo(chemo)therapy: A Call for Caution

Abstract

Background: Emollients used for skin care, treatment of a disease or lubrication, before irradiation during the course of phototherapy or photochemotherapy, may significantly interfere with the transmission of UV light and may influence the outcome of the therapy. Objective: These experiments should characterize and quantify the possible interactions of usual emollients with UV light transmission. Method: The method was an in vitro technique similar to the one already used for the determination of sun protection factors of topical sunscreen preparations. Results: Among the products tested, two showed a significant photoprotection capable of interfering with the course of therapy. Oils enhanced UV light transmission significantly. Conclusion: Emollients may show significant interference with UV light transmission during phototherapy or photochemotherapy. The outcome and course of the therapy could thus be significantly modified.

Enhanced Response of Childhood Psoriasis to Narrow‐Band UV‐B Phototherapy with Preirradiation Use of Mineral Oil

“…Similarly, Berne et al (13) reported that oil‐in‐water emollients can enhance the effectiveness of UV‐B phototherapy. Gabard et al (15) also concluded that emollients can significantly modify the outcome of phototherapy. However, no controlled clinical studies have been published to substantiate this claim in childhood psoriasis.…”

A randomized, double-blind, negatively controlled pilot study to determine whether the use of emollients or calcipotriol alters the sensitivity of the skin to ultraviolet radiation during phototherapy with narrowband ultraviolet B

“…1,3,5,18,19 Two studies 3,5 showed that UV transmission may be enhanced by emollients while two reported the contrary, 1,18 with Otman et al 1 concluding that, in the NB-UVB range, 23 of 30 emollients had a monochromatic protection factor (MPF) of 1AE2 or above -a result considered clinically significant in order to avoid a decrease of UV transmission. 1,3,5,18,19 Two studies 3,5 showed that UV transmission may be enhanced by emollients while two reported the contrary, 1,18 with Otman et al 1 concluding that, in the NB-UVB range, 23 of 30 emollients had a monochromatic protection factor (MPF) of 1AE2 or above -a result considered clinically significant in order to avoid a decrease of UV transmission.…”

Change in ultraviolet (UV) transmission following the application of vaseline to non-irradiated and UVB-exposed split skin

“…This procedure changes the consistency of the substance and creates additional problems with respect to comparability. In most determinations of the UV protection of lubricant emollients performed in vitro , 22,23 the calculated UV protection factor is too high, 24 i.e. the estimated transmission is too low; this is the consequence of paying too little attention to the optical properties of the skin.…”