Experimental models of skin inflammation

The skin is the most accessible organ of the body in which to view the inflammatory process and its pharmacological modulation. However, there are relatively few studies in which the response of the dermal vasculature to inflammatory stimuli has been assessed quantitatively or the chemical mediators of the response measured directly. The mechanisms underlying these responses remain unclear despite the fact that altered microvascular function plays an important part in a number of clinical conditions. This paper describes recent studies in which an experimental model of inflammation in the skin has been used to investigate the pharmacological mechanisms underlying microvascular responses. As allergen-induced cutaneous weal and flare responses are mediated mainly by histamine, we first set out to characterize the vascular responses using the intradermal injection of histamine as a first step, experimental model of allergic skin disease. To quantify the inflammatory responses and to explore the mediator mechanisms underlying them we have combined the techniques of scanning laser Doppler imaging of blood flux and dermal microdialysis to make simultaneous measurements of changes in skin blood flow and the release of mediators within the weal and flare response to intradermal injection of histamine in human skin, in vivo.