When to apply emollients?

It is generally agreed that an optimal time to apply emollients is after a bath. This helps to trap water into the stratum corneum and the warmth of the skin makes applying emollients easier. The trapping of moisture in the skin can be enhanced if the skin is left slightly damp after washing. Whilst it is important that flexures are well dried, to prevent intertrigo, the rest of the skin can be left slightly moist and emollients then applied. This process of ‘soaking and sealing’ moisture into the skin is key in helping rehydrate the skin (Nicol and Boguniewicz, 2008). To reduce the likelihood of the skin becoming very dry overnight, it is always advisable to apply emollient just before going to bed.

There is considerable debate about when to apply emollients in relation to other topical products, particularly topical steroids which are used for patients who have eczema. It is agreed that emollients are of key importance in the treatment of eczema (Akdis et al., 2006); the debate centres around when they should be applied. A number of authors have shown that use of emollients appears to reduce the amount of topical steroid needed to control eczema (Watsky et al., 1992; Lucky et al., 1997; Hanifin et al., 1998; Grimalt et al., 2007). However, these are in no way universally accepted findings. Using biological principles, some would argue that applying an emollient prior to a steroid may reduce its efficacy. The argument used is that the emollient saturates the layers of the stratum corneum preventing effective penetration of the topical steroid to the deeper layers and therefore reducing its efficacy. Currently no robust clinical data exists to support or disprove this point.

Where does this leave the practitioner who is caring for someone with eczema who is using emollients and topical steroids? If an emollient is applied prior to a steroid, consideration should be given to how long it is given to ‘soak’ into the skin before a steroid is applied. The timing will vary, but it is generally accepted that the skin should be tacky but not slippery. Around 30 minutes is usually long enough for this to have happened, but may need to be up to an hour. Similar thoughts should be given to the circumstances around applying a steroid before an emollient. If a steroid is not allowed to sink in properly concerns around diluting the effect of the steroid or smearing onto parts of the body where it is not required may be valid, although Smoker could not find any evidence to back up these concerns (Smoker, 2007). If occlusion is to be applied over topical treatments allowing a time period to elapse may be less important. In the case of wet wrapping for example, applying topical steroid to the areas that need it and then applying emollient elsewhere is a sensible approach (see Eczema for further detail).

In other disease areas like psoriasis, the evidence is even weaker as to the order in which to apply treatments. One unpublished experiment reported by Finlay suggested that the use of emollient improved outcomes for patients treated with dithranol (Finlay, 1997). Whilst it is generally accepted that emollients are helpful adjuvants for the treatment of psoriasis (National Institute for Clinical Excellence, 2001; Hall, 2003), their exact use is hardly explored at all in the literature (Penzer, 2005).

In conclusion, all it is possible to say categorically is that the lack of evidence in this field makes definitive recommendations for practice in this area difficult. The general principles that should guide practice include:

1. Applying active topical medications (e.g. steroids) to well-moisturized skin, is generally preferable than applying them to dry skin;
2. Around 30 minutes should elapse between applying an emollient and an active topical medication. The exact time period will depend upon how dry the skin is and how greasy the emollient;
3. If both emollient and topical steroid have to go on at the same time, applying the steroid to the inflamed areas and the emollient everywhere else is acceptable;
4. If products are being applied under occlusive bandages or dressings, it is probably less important for there to be a gap between the active topical medication and the emollient.