Do we alter ultraviolet sensitivity in vivo with stratum corneum rehydration? A pilot study and review of the literature

Abstract

Although many schemes recommend the administration of emollients prior to UV therapy, there have also been calls for caution, as an uncritical application may interfere with such treatment. We showed that the emulsifying ointments tested exhibited no photoprotective potential and thus are suitable for the pretreatment of psoriasis prior to phototherapy. It has long been discussed whether the effects of emollient pretreatment on response to UV occur only in psoriatic skin or also in healthy skin. Our results indicated that stratum corneum rehydration did not result in a significantly increased erythema response of healthy skin to UVB exposure. With regard to the use of rehydrating cosmetics in everyday life, the outcome of our pilot study is reassuring, as we could not confirm with our experimental design that well-hydrated healthy skin is more prone to actinic damage.

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

“…7,8 Topical agents applied were allowed 30 min to be absorbed before patients' skin was exposed to UVB, which may be important, as previously discussed, when comparing results with studies where emollients were applied immediately prior to UVB. This is in line with two of the studies looking at BB-UVB and emollients.…”

“…7,9,12,13 These reports indicate that the use of salicylic acid 10 or calcipotriol 14 (although De Rie et al 15 concluded that this was more likely to be due to the vehicle than calcipotriol) and thicker applications of emollients 7,9,10,16 are more likely to be responsible. These reports are based on the 'in vivo' use of topical emollients prior to either BB-UVB 7,8,10,12,17 or PUVA. 4,11 Few in vivo reports exist for NB-UVB.…”

“…This is in line with two of the studies looking at BB-UVB and emollients. 7,8 Topical agents applied were allowed 30 min to be absorbed before patients' skin was exposed to UVB, which may be important, as previously discussed, when comparing results with studies where emollients were applied immediately prior to UVB. Whereas De Rie et al 15 found that emollients applied 2 h prior to UVB had no effect on MED readings, we have shown the same to be true when topical agents are applied 30 min before UVB.…”

The impact of emollients on phototherapy: A review

“…Some studies demonstrate that certain emollients have no effect on minimal erythema dose (MED), suggesting that the emollients do not block UV penetration. [16][17][18] Behrens-Williams et al 16 used unguentum emulsificans (cetylstearyl alcohol, paraffin. subliq, Vaseline.…”

A review on the extensive skin benefits of mineral oil

“…Equally, Hudson-Peacock et al [45] found a reduction in MED by 16% for mineral oil. Conversely, Behrens-Williams et al [46] found that an emulsion containing 35% mineral oil, 30% cetylstearyl alcohol and vaseline had no effect on UVB-induced erythema, and Otman et al [47] found that a variety of mineral oil-containing emulsions decreased the sensitivity to UV, but it should be realized that these formulations also contained soft paraffin waxes. The consensus of evidence of the effects of UV irradiation and mineral oil in humans is that mineral oil has a slight, reducing effect on the MED of skin of an order similar to that of glycerol because of its refractive index.…”