The anticomedonic activity of azelaic acid investigated by means of scanning electron microscopy on horny layer biopsy

Hyperkeratosis of the follicular channel is the most commonly demonstrated abnormality in comedonic acne. Several reports have shown the effectiveness of azelaic acid against comedoaes in acne. The aim of this study was to investigate the activity against comedones of 20% azelaic acid (AZA) cream compared with 0.05% retinoic acid (RA) cream and placebo cream using clinical and scanning electron microscopy (SEM) evaluation. Skin surface biop sies with cyanoacrylate glue were performed before and at the end of four months of treatment, and SEM was used to count the number of comedones. The placebo group did not show a reduction in the number of comedones, but there was a significant reduction in the AZA and RA groups. AZA induced a reduction in follicular hyperkeratosis of a similar magnitude to that induced by RA.