Skin barrier function and dermal inflammation. An experimental study of transepidermal water loss after dermal tuberculin injection compared with SLS patch testing.

The reaction of the skin water barrier to dermal inflammation was studied in 15 healthy volunteers. Dermal inflammation was induced either by injection of tuberculin (Mantoux test) or by a 24-h sodium lauryl sulphate (SLS) patch test on the volar forearm. Measurement of transepidermal water loss (TEWL) was used for evaluation of the skin barrier function. Inflammation was quantified by assessment of blood flow by laser-Doppler flowmetry. Measurement from uninvolved skin in the test region > 7 cm distant from the test sites served as control. Measurements were performed twice, separated by an interval of 6 days. Throughout the study, TEWL values were higher in the SLS test sites than in the Mantoux reactions, although the blood flow was significantly increased in Mantoux reactions compared with SLS test sites. This indicates that the impaired skin barrier function caused by SLS is due to a direct cytotoxic effect, and cannot be explained by the inflammatory response alone. At control sites, blood flow and TEWL were significantly higher on the arm with the Mantoux test than the arm with the SLS patch test. The significant inflammation caused by the Mantoux reaction may cause functional alterations in the clinically normal skin > 7 cm distant from the test area.