Two‐dimensional blood flow determinations in allergic reactions using laser Doppler scanning

Abstract

The new technique of laser Doppler scanning (LDS) provides a 2-dimensional pattern of cutaneous microcirculation, which offers a visual image and can quantify the intensity and expansion of perfusion. With the help of this technique, we examined the microcirculatory pattern of Type IV reactions to recall antigens, which were applied using a test stamp (Multitest Merieux). The measurements were performed before application of the test stamp as well as 10 min, 24, 48 and 72 h afterwards. The inflammatory hyperemia was evaluated using LDS and unidimensional laser Doppler fluxmetry. The diameter of the inflammatory infiltrate was quantified by means of palpation, the thickness by means of high-resolution 20 MHz sonography. The clinically visible erythema was measured planimetrically. An unspecific hyperemia resulting from the trauma of the stamp revealed no evident infiltrate under sonography 10 min after the test application. Depending of the individual reaction, the mean flux and the expansion of the hyperemia were at their peak after 48 h. The flux values were at a maximum in the center of the inflammatory reaction and dropped continuously toward the periphery. The area of the hyperemia seen in the LDS image was significantly larger than the expansion of the erythema measured planimetrically, but there was a significant correlation. The perfusion correlated significantly with the infiltration diameter (24 h, 48 h, 72 h) and the infiltration thickness 48 h after testing. All in all, it was possible to measure directly and without touching the skin and to quantify a subclinical pattern of skin perfusion as a response to and inflammatory reaction on a 2-dimensional display.

Quantification of cutaneous pharmacological reactions: comparison of laser Doppler scanning, colorimetry, planimetry and skin temperature measurement

“…With the help of this technique, which does not involve direct contact, the cutaneous microcirculation can be depicted in its 2-dimensional aspect. This technique has been used until now to quantify cutaneous allergic reactions (19), to characterize axon reflexes (9) or perfusion changes after microdialysis (20) and to monitor postoperative wounds (21). The present study investigated which parameter of laser Doppler scanning, skin temperature measurement, planimetry and colorimetry can discriminate the finest variations in local cutaneous reactions and how the parameters of the new technique of laser Doppler scanning correlate with established techniques.…”

Analysis of laser Doppler perfusion images of experimental irritant skin reactions

“…This reduces the possibility of recording very low perfusion components, such as capillary blood flow (18). Stiicker et al (16) used a perfusion profile as an indirect calculation of the reaction size. Due to the irregular shape of the reactions, the spatial variability in perfusion and the subjectivity in the threshold setting of the perfusion profile, this method may introduce errors in area determination.…”

“…In the assessment of skin blood flow, Quinn et al (14) used the laser Doppler scanner, developed by Essex et al (15), in dose-response tests to measure both the blood flow intensity and the area of the contact allergic inflammation. Stiicker et al (16) used the laser Doppler perfusion imager (LDPI) (17) for the assessment of blood flow in allergic reactions.…”

Effect of dark test‐substance pigmentation on skin perfusion assessments and effect of test technique on balsam of Peru patch‐test results

“…A software application permits direct assessment of a scanned area or a part thereof. The scanning technique has been used for various investigative purposes (10)(11)(12)(13), but in a very limited way for patch tests. We have primarily used the technique for allergic patch-test assessments and to compare perfusion and visual assessments of patch tests (14)(15)(16)(17).We have also used the technique to investigate reactivity caused by diesel oils (18), and to test the effect application devices may have on patch-test results (19).…”