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Instrumental evaluation of subclinical responses to 0.05% NiSO(4) patch tests
A d Nardo1, M E Schiavi1, S Seidenari1
1Department of Dermatology, University of Modena, Italy.
Background/Aims:
The possibility of identifying allergic reactions while they are not clinically evident could prove extremely useful in studying the evolution of skin responses in experimentally-induced contact dermatitis. In drug research and in cosmetological research, the sensitizing properties of new molecules or haptens present in the product in a low concentration also need be clarified. The object of the present study was to validate noninvasive techniques and their use for the study of subclinical allergic reactions.
Methods:
70 nickel-sensitized subjects previously standard tested with 5% nickel sulphate in petrolatum were challenged with a 0.05% nickel sulfate solution on the volar aspect of the forearm, application for 24 h and measurement at 72 h. Colorimetry, evaporimetry (transepidermal water loss, TEWL) and high-frequency echography were used to characterize reactions.
Results:
Colorimetry and TEWL did not show any significant differences between patch test areas and control areas. Skin thickness determination, conversely, evidenced a significant increase both with respect to baseline values and control areas.
Conclusion:
Echographic evaluation is able to detect modification of skin thickness of subclinical allergic patch test reactions to nickel sulfate while colorimetry and TEWL failed to detected such minute changes.
