[Irritation cutanée et vitesse de propagation d'ondes ultrasonores]

Cutaneous irritation is a stereotyped response of the skin to any physical or chemical insult. Its main manifestations encompass inflammatory erythema and an alteration of the cutaneous microrelief showing increased roughness, dehydration and erratic desquamation. Several instrumental methods can indirectly assess the issues of cutaneous irritation on human stratum corneum. The aim of the present study was to measure the speed of propagation of ultrasound shear waves in the skin irritated by anionic surfactants. The study was performed in 25 healthy subjects of both sexes. Occlusive patches of a 10% solution of anionic surfactants were applied to a forearm of each volunteer. The other forearm served as an untreated control site. Patches remained in place for 24 h. Three hours later, another patch was placed again for 21 h. Resonance running time measurements (RRTM) of the ultrasound shear wave were performed using a Reviscometer RVM 600. Measurements were performed at entry in the study and 2 days after removing the second patch. Desquamative xerosis was obvious at the sites patched with the surfactant solution. RRTM values were significantly (P < 0.0001) lower than those at the control site. Hence, the speed of propagation of ultrasound shear waves was shown to be increased at an irritated site compared to an intact site. In conclusion, this study shows that the propagation speed of ultrasounds is influenced by the skin surface nature, being considerably increased in skin altered by surfactants.