Modified phenol chemical face peels: recognizing the role of application technique.

To determine the relative roles of phenol concentration, croton oil concentration, and application techniques, the authors obtained three additional human biopsy studies. The last study was a randomized, controlled, prospective study with surgeon, pathologist, and third-party evaluators blinded during the application process and during the gross and histologic evaluations. Conclusions drawn from the findings of the studies included the following: Rubbing more coats of phenol, with or without croton oil, produces more inflammation and fibrosis. Adding croton oil reduces the threshold of injury from 20 to 50 coats to 5 to 20 coats applied with a cotton tip applicator, confirming the clinical impression that croton oil resin facilitates injury pattern of wounding when used with phenol in 35% to 88% concentrations. 48% phenol without croton oil can provide the same long-term results as 48% phenol with croton oil. The data suggest that the application technique is more important than the concentration of phenol or croton oil alone.