Moisturizers are used as prevention and treatment of surfactant and irritant dermatitis. Occlusives, humectants and hydrocolloids can be used to improve the function of the skin water barrier by increasing the moisture content.
Moisturizer efficacy remains unresolved. This evidence-based overview attempts to place the conflicting literature sources into a clinical and product development perspective.
Material and Methods
As an update to a previous overview by Zhai and Maibach, publications from 1992 to 2006 were reviewed quantitatively to examine moisturizer effectiveness. Pub Med from 1992 to 2006, Science Citation Index from 1992 to 2006, and Embasea from 1992 to 2006 were searched on these terms: moisturizer, irritant dermatitis, prevention and treatment.
Results on Prevention
Preventing ICD in normal skin: Of the 10 studies performed on normal skin, those by Held and Agner and Held et al. suggest that using Locobase on normal skin caused increased susceptibility to experimental irritants. Ramsing and Agner4 had the opposite experience with this product. Direct comparison is problematic because different anatomical sites and exposure duration were used.
Held and Agner compared two moisturizers on normal skin. Nineteen healthy volunteers applied them three times daily for five days before 24-hr patch testing with sodium lauryl sulfate (SLS). Evaluation, including transepidermal water loss (TEWL), electrical capacitance, laser Doppler colorimetry and clinical scoring concluded that SLS skin response was increased on moisturizer-treated arms compared to controls for Locobase, while this was not statistically significant for the other moisturizer, Decubal. This difference is most likely because of lipid content. Those authors suggest that increasing stratum corneum (SC) hydration enhances permeability to hydrophilic substances. A high level of SC hydration may facilitate transportation of a hydrophilic allergen, and this is likely to be positively related to lipid moisturizer content.