Dose-response relationships for topically applied antigens.

Patch-test responses to serially diluted nickel sulphate and potassium dichromate solutions in patients with nickel and chrome sensitivity were assessed by pulsed A-scan ultrasound to determine skin thickness and laser-Doppler flowmeter techniques to evaluate blood flow, as well as clinical scoring. There was a relationship between the dose of antigen and the test responses as measured by ultrasound and laser-Doppler flowmeter techniques in both nickel and chrome sensitive patients. Our data suggest that both techniques may be useful in the detection of allergic contact dermatitis in which there is a doubtful patch-test reaction as well as in experimental sensitization studies.