Digital image analysis of erythema development after experimental thermal injury to human skin: effect of postburn topical local anesthetics (EMLA).
Local anesthetics inhibit edema and improve circulation in experimental burns. We evaluated the effect of topical local anesthetics on human skin burns in volunteers using computerized color analysis that allowed repeated noninvasive quantitative measurements. A standardized partial-thickness burn (1 cm2) was induced in one forearm of 10 healthy volunteers and in the opposite forearm a week later. The burned areas were treated with lidocaine/prilocaine cream (EMLA; Astra, Sweden) or a placebo cream for 1 h. The experimental skin area was photographed before and 1, 2, 4, and 12 h postburn. Digitized images were evaluated using normalized red-green-blue and Hue-Saturation-Intensity. Differences in erythema between skin treated with EMLA 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 reduces the duration of erythema after a mild thermal injury, which suggests a potential use in clinical practice in the treatment of minor skin burns.


CONCLUSIONS
Burn injury constitutes a serious type of tissue damage that activates inflammatory mechanisms, often causing pain, disfiguration, or malfunction. We treated burns using an anesthetic cream and demonstrated a reduction in burn-induced inflammation by using computer-based color image analysis.
D000287:Administration, Topical; D000328:Adult; D019162:Anesthetics, Combined / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002056:Burns / Q000188:drug therapy*; D004890:Erythema / Q000188:drug therapy*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008012:Lidocaine / Q000008:administration & dosage*; D000077442:Lidocaine, Prilocaine Drug Combination; D009824:Ointments; D011318:Prilocaine / Q000008:administration & dosage*