Digital image analysis of erythema development after experimental thermal injury to human skin: Effect of postburn topical local anesthetics (EMLA (R))

Local anesthetics inhibit edema and improve circulation in experimental bum s. We evaluated the effect of topical local anesthetics on human skin burns in volunteers using computerized color analysis that allowed repeated noni nvasive quantitative measurements. A standardized partial-thickness burn (1 cm(2)) was induced in one forearm of 10 healthy volunteers and in the oppo site forearm a week later. The burned areas were treated with lidocaine/pri locaine cream (EMLA(R); Astra, Sweden) or a placebo cream for 1 h. The expe rimental skin area was photographed before and 1, 2, 4, and 12 h postburn. Digitized images were evaluated using normalized red-green-blue and Hue-Sat uration-Intensity. Differences in erythema between skin treated with EMLA(R ) and placebo were not significant during the first 4 h postburn. However, 12 h postburn, a pronounced decrease in the degree of erythema was observed in EMLA-treated skin compared with placebo-treated skin. We conclude that topical local anesthetics administered for 1 h postburn significantly reduc es the duration of erythema after a mild thermal injury, which suggests a p otential use in clinical practice in the treatment of minor skin bums. Impl ications: Burn injury constitutes a serious type of tissue damage that acti vates inflammatory mechanisms, often causing pain, disfiguration, or malfun ction. We treated burns using an anesthetic cream and demonstrated a reduct ion in burn-induced inflammation by using computer-based color image analys is.