title: Assessment of irritant skin reactions using electrical impedance--a comparison between 2 laboratories.
abstract: To assess interlaboratory variability in the measurement of skin electrical impedance (IMP), we evaluated irritant reactions to sodium lauryl sulfate (SLS) (2%) and nonanoic acid (NAA) (40%) in 2 laboratories. We studied the patch test responses in 40 healthy male and female volunteers between 20 and 30 years of age (20 in each laboratory) with an instrument for measuring IMP. 2 other bioengineering methods and visual scoring were also used to facilitate further illumination of any findings. A strict protocol including all details of the measurement procedure was carefully implemented in both laboratories. The skin reactions were evaluated at 23 h and at 3, 7 and 14 days after exposure. Our findings show that both irritants caused distinct dynamic responses detectable with the bioengineering techniques. Interestingly, the IMP baseline values varied between the 2 laboratories. Moreover, at early stages in the development of irritation (day 1), the irritants induced changes in IMP indices in the opposite direction, which accords with the concept of various IMP patterns of contact dermatitis caused by different irritants. Although the absolute values of IMP differed in both laboratories, the dynamic response patterns were the same.
authors.affiliation: Karolinska Institutet, Department of Medicine, Section of Dermatology and Venereology, Huddinge University Hospital, Stockholm, Sweden. natalia.kuzmina@medhs.ki.se
authors.forename: Natalia
authors.initials: N
authors.lastname: Kuzmina
authors.forename: Celine
authors.initials: C
authors.lastname: Duval
authors.forename: Stina
authors.initials: S
authors.lastname: Johnsson
authors.forename: Anders
authors.initials: A
authors.lastname: Boman
authors.forename: Magnus
authors.initials: M
authors.lastname: Lindberg
authors.forename: Lennart
authors.initials: L
authors.lastname: Emtestam
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002138:Calibration; D017453:Dermatitis, Irritant / Q000175:diagnosis* / Q000209:etiology; D017097:Electric Impedance; D005227:Fatty Acids / Q000009:adverse effects; D005260:Female; D006801:Humans; D007509:Irritants / Q000009:adverse effects*; D008297:Male; D015588:Observer Variation; D010328:Patch Tests; D012680:Sensitivity and Specificity; D012967:Sodium Dodecyl Sulfate / Q000009:adverse effects
chemical_list: D005227:Fatty Acids; D007509:Irritants; D012967:Sodium Dodecyl Sulfate; C008776:pelargonic acid