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Comparison of three methods of using the DermaPIK with the standard prick method for epicutaneous skin testing
1Department of Pediatrics, West Virginia University, Morgantown, USA.
Background:
The Greer DermaPIK is a plastic disposable device used for epicutaneous allergy skin testing. Various methods have been proposed for applying this device. The recommended methods are to use it as either a punch or scratch device. A third method- the prick, uses the device similarly to standard prick testing with the bifurcated needle.
Objective:
To compare three methods of using the DermaPIK for epicutaneous skin testing with the bifurcated needle.
Methods:
Twenty volunteers with a mean age of 30 years (range 6 to 45) were skin tested using saline and histamine. Each test was done in triplicate on the back. Discomfort for each technique was rated on a scale from 0 to 100. Wheal and erythema were measured at 15 minutes and a photograph was taken.
Results:
The scratch method was rated highest in discomfort. The mean coefficient of variation for the punch method was 39.2% for erythema which was significantly higher than for the other methods (P < .0001). The scratch method had a mean wheal and erythema to saline of 3.85 +/- 1.3 and 6.23 +/- 2.2 that was significantly larger than the other methods (P < .001). There was no difference between the prick method and the bifurcated needle for discomfort or size of wheal/erythema to saline or histamine.
Conclusions:
The punch method is too imprecise and the scratch method produces considerable dermatographism. The prick method was comparable to the bifurcated needle in discomfort, sensitivity and precision.