Patch testing with sodium lauryl sulfate:: benefits and drawbacks in research and practice

Patch testing with sodium lauryl sulfate (SLS) has been frequently used in the last decade. The evaluation of the SLS test can be performed visually, or with bioengineering methods. Among these,the transepidermal water loss is the most appropriate method, but measurements by laser Doppler flowmetry, colorimetry or corneometry may yield additional relevant data. Various factors such as age, area of testing or climatic conditions may also influence the SLS test, so such factors should be considered when different studies are compared. If correctly used, the SLS test can provide valuable information regarding the skin susceptibility to irritation. An overestimation of the test,just based on objective measurements with bioengineering methods, should be avoided, as the bioengineering data are capable of great precision and reproducibility, but can only define phenomena and nor the causal event.