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Quantification of allergic and irritant patch test reactions using laser‐Doppler flowmetry and erythema index
Author(s) -
Gawkrodger David J.,
McDonagh Andrew J. G.,
Wright Andrew L.
Publication year - 1991
Publication title -
contact dermatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 96
eISSN - 1600-0536
pISSN - 0105-1873
DOI - 10.1111/j.1600-0536.1991.tb01693.x
Subject(s) - erythema , laser doppler velocimetry , patch test , dermatology , blood flow , medicine , benzalkonium chloride , irritation , allergy , chemistry , pathology , immunology
The laser‐Doppler blood flow and erythema index were assessed in 16 patch test reactuibs caysed by irritants (1% aq. Sodium lauryl sulphate and 1%aq. Benzalkonium chloride) and in 13 varied allergic reactions, at 2 or 4 days. Both irritant and allergic responses produced satistically significant increases in laser‐Doppler flow index and erythema index compared to control sites ( p <0.05 or less, using the Wilcoxon rank‐sum test). A disproportionately greater increase in erythema index than in laser‐Doppler flow was seen in mild irritant reactions, compared to allergic, though the two could no be reliably distinguished by these tests. 2 non‐allergic nickel sulphate sites produced an increase in both blood flow and erythema without any clinical change. Petrolatum alone produced no significant change in either measurement. The laser‐Doppler flow showed an overall correlation with the erythema index (product moment method: r =0.55. p <0.001), but there was little correlation between these indices and patch test reactivity as judged clinically by conventional scoring. Generally, allergic and irritant patch test reactions could not be differentiated on the basis of laser‐Doppler flow index for mild irritant responses warrants further study in other irritant models.