Histamine skin prick tests: from established diagnostic technique to advanced experimental biomarker

Introduction Skin prick tests have a long history as diagnostic and pharmacodynamic biomarker. Besides visual assessments of the wheal and flare, objective blood flow measurements using laser Doppler imaging (LDI) and laser speckle contrast imaging (LSCI) have been reported. In light of these advancements, an up-to-date characterization of the histamine-evoked response is worthwhile. Methods A single-center study was completed in healthy males. Two parameters were addressed: (1) dermal blood flow (DBF) within a 7.65 mm ring encircling the skin prick site (DBFring), and (2) surface area of the flare (AREAflare). First, the dose response was assessed using placebo (0.9% sodium chloride) or histamine (histamine dihydrochloride 1, 3 or 10 mg/mL) skin pricks on the volar surface of subjects ’ (n=12) forearm. The DBFring was measured by LDI, the AREAflare by LDI and by ruler. Secondly, the inter-arm and inter-period reproducibility of the DBFring and AREAflare, as evoked by histamine (10 mg/mL) and measured by LDI and LSCI, was examined (n=14). Lastly, the effect of aprepitant (125 mg ), ketotifen (1 mg) and a single (5 mg) and fourfold (20 mg) dose of desloratadine and levocetirizine on the histamine-induced (10 mg/mL) DBFring and AREAflare was evaluated with LSCI (n=13 or 12). Results All three histamine doses induced a time-dependent vasodilation. Ruler recordings did not con clusively correlate with LDI assessments of the AREAflare. The DBFring and AREAflare were reasona...
Source: Skin Pharmacology and Physiology - Category: Dermatology Source Type: research