Scanning Laser Doppler Imaging and Dermal Microdialysis in the Investigation of Skin Inflammation

Martin K. Church & Geraldine F. Clough

Abstract:

Scanning laser Doppler imaging, used to access quantitatively changes in dermal blood perfusion, and dermal microdialysis, to sample the biochemical mediators released in the dermis, are two recently developed techniques which may be applied to the investigation of the mechanisms of human skin in vivo. This article reviews information gained by their use, both individually and together, about the wheal and flare responses induced by histamine and bradykinin. In summary, we have assessed the rate of development of the dermal responses to these mediators and demonstrated the irregular nature of the areas of increased perfusion within the flare. Using microdialysis, it has been shown that histamine, while reaching high levels close to its site of injection at the center of the wheal, is not released secondarily in the flare. Finally, it has been shown that, in the majority of individuals, negligible amounts of histamine are released in the wheal and flare induced by bradykinin, and yet the responses are inhibited more than 70% by the antihistamine cetirizine. This potentially new action of histamines is being investigated further.