Skin biopsies obtained at the conclusion of the placebo-controlled trial were stained for 5-LO cells (A), macrophages (B), and neutrophils (C), and cell counts were performed in a blinded manner. (*P = 0.02, **P = 0.001, Mann-Whitney U test). Representative cutaneous histology stained for 5-LO obtained at the conclusion of the trial in the placebo (D) and ketoprofen (E) groups (20×, and magnified insets). Red arrows indicate 5-LO–positive cells.