The rotating wire brush treatment for acne scars recently reported1 has been of value in my experience. However, freezing of the skin with the ethyl chloride spray obscures the scars, making it difficult to locate the exact areas to be treated.
A technical improvement which I have found helpful is the use of 1% methylrosaniline chloride N. F. (gentian violet) to delineate the scarred areas. At first it was used only to outline the desired areas, but further experience has shown the advantage of painting the entire area to be treated. Not only does the methylrosaniline chloride delineate the area to be treated, but the rotating wire brush removes the dye with each stroke, showing the exact area which has been treated. This is very advantageous, because the frozen skin does not bleed and it is difficult to determine the effective width of each stroke of the brush