The greatest effect of the use of oral antibiotics probably occurs during the first 6–8 weeks of treatment, and the best data at this time would appear to derive from the two studies using doxycycline.16,44 Certainly, the CYTAR trial is the largest randomized trial to date to investigate the prophylactic use of a drug against EGFR-targeted agent-induced skin rash, and while the overall incidence of skin rash was not reduced, patients receiving doxycycline showed a significant reduction in the severity of their erlotinib-induced folliculitis and significantly less impairment of their QoL. This evidence concerns the gene EGFR and folliculitis.