The treatment of alkaline burns of the skin by neutralization

Literature reports dating as far back as 1927 have lured clinicians into the belief that alkaline skin burns are best treated by water dilution and that neutralization attempts should be avoided. Although this belief has never been substantiated, neutralization of an alkaline burn of the skin with acid was thought to increase tissue damage secondary to the exothermic nature of acid-base reactions. The authors proposed that topical treatment of alkaline burns with a weak acid such as 5% acetic acid (i.e., household vinegar) would result in rapid tissue neutralization and reduction of injury in comparison to water irrigation alone. In a rat skin burn model, animals were exposed to an alkaline injury when filter paper (2 cm in diameter) saturated with 2N sodium hydroxide was placed over the volar aspect of the animal for a period of 1 minute. Treatment was initiated 1 minute after injury and included either neutralization with a 5% acetic acid solution (n = 8) or irrigation (n = 8) with water. Skin temperature and pH were monitored using subdermal needle probes until the pH of the skin returned to physiologic values. Punch-biopsy specimens were obtained from the wound edges 24 hours after injury to assess burn depth and leukocyte infiltration, and biopsies were repeated 10 days later to assess wound healing. The authors proposed that neutralization of an alkaline substance with household vinegar (i.e., 5% acetic acid solution) would result in rapid neutralization and thus reduce extent of tissue injury. Animals treated with acetic acid demonstrated a more rapid return to physiologic pH (14.69 +/- 4.06 minutes versus 31.62 +/- 2.83 minutes; p < 0.001), increased depth of dermal retention (0.412 +/- 0.136 mm versus 0.214 +/- 0.044 mm; p = 0.015), decreased leukocyte infiltrate (31.0 +/- 5.1 cells/high-power field versus 51.8 +/- 6.8 cells/high-power field; p < 0.001), and improved epithelial regeneration (4.0 +/- 0.6 cell layers versus 1.7 +/- 0.5 cell layers; p < 0.001) when compared with animals treated with water irrigation. No difference was detected in peak pH (10.35 +/- 0.28 pH versus 10.36 +/- 0.25 pH; p = 0.47) nor in rise of skin temperature (maximum temperature, 32.8 degrees C versus 32.9 degrees C; p = 0.33) between acetic acid-neutralized and water-irrigated burn wounds. The observed benefits of treating alkaline burns with 5% acetic acid in the rat model are significant and require clinical testing.