Inflammation of actinic keratoses induced by cytotoxic drugs

degrees of blanching do occur with such preparations. In any event, in the multiple reading technique of the vasoconstrictor assay, if Haigh et al. are correct, a similar degree of error would occur in the early readings and this weakens the argument used to justify their statements. Clearly, the total time between application of materials and taking the reading is a highly relevant factor, as corticosteroids take several hours to produce a blanching response. This total consists of the period during which the test materials are in place on the skin and the interval of time after their removal until the first reading has been made. In the single reading technique which we used, assessments were made 7 h are application of test materials (including i h after their removal) and in a large series of vasoconstrictor assays we have not encountered any particular difficulty in performing the readings. Furthermore, extremely good correlation was found between results obtained by the three independent scorers who performed their assessments under double-blind conditions. The excellent correlation between results produced by experienced readers of the vasoconstrictor assay, and the reproducibility of the technique following visual assessment, have convinced us that more sophisticated methods of assessment are unlikely to be superior to the relatively simple but reproducible technique which we have utilized.