An accurate photographic method for grading acne: initial use in a double-blind clinical comparison of minocycline and tetracycline.

This investigation utilized an accurate photographic method and grading scale for evaluating acne in sixty-two patients. During a randomized double-blind clinical study in which half of the patients received minocycline and half, tetracycline, photographs of facial or body acne were taken at baseline and every 2 weeks over a 12-week period of therapy. In addition to on-site blinded gradings by both the investigator and the patients, separate assessments were made by two independent dermatologists utilizing the scale and the transparencies taken during the study. A reasonable agreement was found between the investigator, the patients, and the independent dermatologists, indicating the usefulness of this method. The investigator's rating of acne severity disclosed a significantly (p less than or equal to 0.05) more rapid clinical response at weeks 2 and 8 in the patients who received minocycline than in those who received tetracycline. Also, the assessment of one of the independent dermatologists showed a significantly (p = 0.024) better response to minocycline than to tetracycline at week 8 of therapy. The incidence of adverse clinical experiences was lower in the minocycline-treated group (10%) than in the tetracycline-treated group (22%).