Assessment of skin irritancy in man by laser Doppler flowmetry

It is desirable to use more objective methods than visual storing for the assessment of skin irritancy reactions. In the present study the blood flow in skin sites exposed to sodium lauryl sulfate (SLS) was recorded by a laser Doppler flowmeter. The irritant was applied to the volar forearm of healthy volunteers in concentrations ranginig from 0.001% to 5% under occlusion for 24 h. The test sites were scored visually and the blood flow was recorded at 3 different times: 26 h, 48 h and 72 h after the application of SLS. Approximately 950 recording were performed and a clear relationship was observed the applied doses of SLS, the recorded blood flow values and the corresponding scores. In a few cases a deviation from the general trend was observed, implying that the naked eye might be unreliable for the assessment of skin irritancy reactions.