VASCULAR AND SENSORY RESPONSES OF HUMAN SKIN TO MILD INJURY AFTER TOPICAL TREATMENT WITH CAPSAICIN

Abstract

1 Immediately after several topical applications of capsaicin at 2-hourly intervals, human forearm skin would no longer develop flare (vasodilatation) around a small injury. At the same time heat pain thresholds were reduced on average by 3.5°C. These results are consistent with block by capsaicin of the effector side of the axon reflex, perhaps by depleting nerve terminals of substance P. 2 Over a period from several days to several weeks after treatment, flare was diminished and heat pain thresholds were slightly elevated. These changes may be due to long-lasting damage of cutaneous nerve terminals by capsaicin.