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Bath emollients for atopic eczema: why use them?
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Emollient preparations play a central role in the treatment of people with dry skin associated with conditions such as atopic eczema.1,2 As well as being advised to apply emollient creams or ointments directly to the skin, people with atopic eczema are commonly prescribed bath emollients.3 Each year, the NHS spends over £16million on bath emollients (at an average cost of £6.29 per item).4 This represents 38% of the total cost of treatments prescribed for preschool children with eczema, matching the proportion spent on emollients for application directly to the skin.5 What clinical contribution do bath emollients make in the treatment of people with atopic eczema?

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Applying emollients directly to the skin

Emollients are commonly used in the form of creams, lotions, gels or ointments intended for direct application to the skin. Such emollients are an important part of treatment for patients with atopic eczema and other dry skin conditions such as ichthyosis, psoriasis and pruritus with advancing age. They are widely used to improve the symptoms and appearance of dry skin, to prevent skin cracking and to reduce dependence on topical corticosteroids. The rationale for this is that, in theory, they improve the skin's condition by forming an occlusive layer, preventing water loss from the skin and preventing irritants from coming into contact with the skin.6 This idea appears to have some support from evidence that impairment of the skin's barrier function plays an important role in the development of atopic eczema.7 Emollients may also add water to the skin.

Published evidence

There is very little published evidence on the clinical effects of topical emollients in atopic eczema. A systematic search for evidence from randomised controlled trials found insufficient data to allow assessment of the efficacy of the products.8

Evidence from one published non-blinded randomised controlled trial has suggested that regular application of emollients directly to the skin might reduce the amount of topical corticosteroid used to treat atopic eczema.9 The trial involved 173 infants (aged under 12 months) with moderate–severe atopic eczema. For the treatment of eczematous inflammatory areas of skin, the parents of all the children were supplied with a topical corticosteroid (micronised desonide 0.1% cream and/or desonide 0.1%, described by the investigators as high and moderate potency preparations, respectively; neither is available in the UK). The parents of one group of the children were also instructed to apply an emollient (a French product containing oat extract) to dry, non-inflamed areas of the skin over the whole body, twice daily for 6 weeks. The control group received no emollient. Use of any other emollient product was forbidden during the study. By the end of the trial, the amount of topical corticosteroid used (the primary outcome measure) was less in the group who used emollient compared to the control group, but the difference was statistically significant only for high-potency corticosteroid use (42% less was used: 8.56g vs. 14.7g, p=0.025). Limitations of this study included that the number of participants (210) was fewer than planned, as well as the fact that participants and investigators were not blinded to treatment allocation.

Clinical experience and guidelines

While there is scant evidence on efficacy from clinical trials, long clinical experience has suggested that emollients applied directly to the skin are effective and safe. National eczema treatment guidelines recommend that they be applied liberally, regularly and as frequently as possible,1,2 commonly 2–3 times daily, including after bathing. There are many different topical emollient formulations available.10 Ointments, which are greasier than creams and lotions, are generally regarded as more effective in improving dry skin and as having a longer-lasting effect, but people often find creams and lotions nicer to use. It is generally considered that giving patients a choice of emollient is likely to result in their choosing one that they will use frequently and regularly.1, 2, 10

Washing with emollients

Patients with atopic eczema are usually advised to avoid using soaps and detergents (such as bubble baths) for washing because these can irritate the skin.1,2 Emulsifying ointment and aqueous cream are emollients that can be washed off the skin and are commonly prescribed as soap substitutes.10 Patients are also often advised by healthcare professionals to add a bath emollient to bath water. This is sometimes done in the belief that it is an easier way of applying an emollient to a large skin surface area, particularly for children who may not cooperate with having topical emollients applied frequently. The advice also aims to encourage people to change from using potentially irritant preparations such as bubble baths. Some published sources of prescribing advice encourage the use of bath emollients. For example, the Clinical Knowledge Summaries service (formerly published as PRODIGY guidance) advises that a bath emollient should be prescribed for anyone with moderate, severe, or widespread dry skin.2 Similarly, a patient information leaflet from the British Association of Dermatologists advises bath additives “help to prevent the loss of moisture from the skin”.11 Some of the summaries of product characteristics of bath emollient preparations recommend “it is important to use an emollient while bathing”. Regular use of a bath emollient is included in the concept of “complete emollient therapy” recommended in some eczema treatment guidelines, that is, that “continual treatment with complete emollient therapy (combinations of cream, ointment, bath oil and emollient soap substitute) will provide maximal effect”.1

Types of bath emollient

Several emollient bath preparations are available for NHS prescription (see table).10 The main ingredients in most are liquid paraffin together with another emollient, most commonly wool fat or isopropyl myristate. Three preparations contain antimicrobials (benzalkonium chloride alone or with triclosan). These are licensed for “prophylactic treatment of eczema at risk from infection”,12 or to “assist in overcoming secondary infection”.13,14 However, national guidelines advise that such products should not be used regularly unless infection is widespread or recurrent.1,10 A few preparations contain lauromacrogols (which are surfactants), the inclusion of which in an emollient is claimed to help break the itch-scratch cycle, according to some guidelines.1

Bath emollients are mainly intended for adding to bath water (in various amounts). The instructions for many of the products say they can be rubbed undiluted onto wet skin before showering and rinsed off, whereas a few can be rubbed onto dry skin. Some are not recommended by the drug companies for undiluted use. All of the products can be bought over the counter (at a higher cost than to the NHS).

Clinical research on bath emollients

There is no published evidence from randomised controlled clinical trials evaluating the efficacy of bath emollients in the treatment of patients with atopic eczema. In particular, no trials have addressed the following questions: how using a bath emollient compares with having a water bath using a suitable emollient as a soap substitute followed by direct application of a topical emollient to the skin; and whether using a bath emollient affects overall use of emollient therapy (i.e. whether patients might forgo direct application of emollients to the skin, thereby undermining the effectiveness of this therapy).

Two published controlled trials have attempted to assess the effects of bath emollients containing antimicrobials in patients with eczema.15,16 We reviewed this evidence in our article on antiseptic/emollient preparations in 1998.17 Both trials were comparisons of the ‘medicated’ version of one product with the standard version of the same product and neither showed any clinical benefit from using antimicrobials in this way. No new evidence assessing the efficacy of these products has been published in the meantime and so our original conclusion is unchanged: the routine use of antiseptic/emollient preparations in patients with atopic eczema cannot be recommended.17

There is no published evidence to confirm that bath emollient preparations containing lauromacrogols prevent itching.

Unwanted effects

Irritation or allergic contact dermatitis has occasionally been associated with use of bath emollients containing antimicrobials.18,19 Emollients can make baths slippery, which may lead to accidents. They can also leave a greasy film in the bath, making it more difficult to clean.

Opinion vs. evidence

The lack of published evidence of efficacy is common to emollients for direct application to the skin and bath emollients. However, there is a consensus among clinicians (as well as supporting data from the recently published randomised controlled trial9) to indicate that emollients applied directly to the skin are effective. The same cannot be said of bath emollients. We know from our consultations while preparing this article that some clinicians question the view that bath emollients are an essential component in the treatment of patients with atopic eczema.


Topical emollients applied directly to the skin are key in the management of patients with atopic eczema, and there is long clinical experience and some published evidence to justify such use. Bath emollients are also prescribed for many patients who have atopic eczema but the basis for their use is much more questionable. Not only are there no published randomised controlled trials on bath emollients in atopic eczema, there is no consensus of clinical opinion that such therapy is effective. Given that bath emollients are expensive and the NHS spends a considerable sum on them, we believe that their use requires proper evaluation. In particular, it would be helpful to know how using a bath emollient compares with having a water bath using a suitable emollient as a soap substitute followed by direct application of a topical emollient to the skin. Another key question to be answered is whether using a bath emollient affects patients' overall use of emollient therapy. We believe that, in the absence of such evidence, treatment strategies in which patients successfully apply emollients to the skin without ever using bath emollients are entirely reasonable.


[M=meta-analysis; R=randomised controlled trial]

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