Quantification of allergic and irritant patch test reactions using laser‐Doppler flowmetry and erythema index

Abstract

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 (pr=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.