Background: Moisturizers are widely used for atopic dermatitis (AD) and related conditions, but available evidence of their effectiveness has not been reviewed in a systematic fashion.

Objectives: Our objective was to investigate the effectiveness of emollients, as a group and individually, in the treatment of AD and related conditions, by means of a systematic review.

Data sources: Studies indexed in MEDLINE and/or Embase before 16 January 2015.

Study eligibility criteria: Controlled clinical studies comparing the clinical effect of a moisturizer against its vehicle, another moisturizer, or no treatment were eligible. For the outcomes transepidermal water loss (TEWL) and stratum corneum hydration, uncontrolled before-after designs were also eligible.

Participants: Participants were patients with AD, irritant hand dermatitis, and/or ichthyosis vulgaris.

Results: Out of the 595 publications initially identified, 45 (48 studies, 3262 patients) were eligible for inclusion. A vast majority of studies indicate that moisturizers have beneficial effects on clinical symptoms [SCORAD (SCORing Atopic Dermatitis) reductions ranging from 0 to 2.7 points], TEWL (range 0 to -12.2 g/m(2)h) and stratum corneum hydration (range +8 to +100%). Direct comparisons between individual moisturizers are still scarce, but the clinical effect appears to be much more well-documented for urea and glycerin than, for example, propylene glycol, lactate, ceramide, and aluminum chlorohydrate. Compared with urea studies, glycerin studies were more often associated with a high risk of bias.

Limitations: Due to differences in study designs and outcome measures, a quantitative meta-analytic approach was not deemed feasible, and formal indicators of publication bias such as funnel plots could not be used. However, a large number of moderately sized studies with positive outcomes could be compatible with selective publishing of favourable results.

Conclusions: The clinical effect of moisturizers is well-documented. Urea-based preparations may be preferable as a first-line treatment, but there is an unmet need for well-powered comparisons between individual moisturizers.