An open assay model to induce subclinical non-erythematous irritation

To avoid the acute irritation and dryness that a single occlusive surfactan t application (24-h patch test) may cause, and to approximate clinical use, an open application model was chosen to define subclinical non-erythematou s irritation in the stratum corneum. This human test combined a supervised washing at the laboratory with at-home use of the test products by the subj ects. Effects of washing with the surfactants on the dorsal hand and volar forearm were compared. The results demonstrated that this situational use m odel permits the exploration of subclinical surfactant-induced irritation. The forearm appeared to be more discriminative as compared to the dorsal ha nd. Squamometry proved to be a sensitive, complementary assessment method f or detecting surfactant-induced subclinical skin surface alterations and fo r differentiating surfactant effects in this open assay.