Effects of washing acid injuries to the skin with water: an experimental study using rats.

A skin acid injury model has been constructed using SD rats and 1N HCl. The changes over time, with particular attention to subcutaneous tissue pH, were recorded and included a comparative study of the effect of washing with water at 1, 3 and 10 min after injury, on subcutaneous tissue pH. After inflicting an acid injury, the subcutaneous tissue pH of control animals reached its minimum value at the seventh minute, and had not recovered to the pre-experimental level by the 60th minute. In the group of rats which was washed at 1 min, the pH did not drop below 7.5, it remained virtually unchanged. In the group washed at 3 min, the pH declined slightly, but subsequent to washing, the pH increased gradually. In the group washed at 10 min, the changes in pH were almost the same as those in the untreated group. These results indicated that if washing was carried out before the subcutaneous tissue pH level reached a minimum value, any remaining acid on the skin surface could be washed away, effectively suppressing the subsequent fall in pH.