Dermal healing after local skin flaps and chemical peel

Like cells respond to injury through repair mechanisms unique for each cell type (eg, regeneration of the epidermis, granulation over exposed fat). How simultaneous chemical peel affects a local skin flap and why minimal differences in chemical peels can result in significant differences in outcome is not fully understood. In this study guinea pig skin was exposed to skin flap elevation, chemical peel, or a combination of the two. Biopsy specimens were taken at 3 to 35 days after injury and the histologic sections were studied. Results demonstrate that (1) lifting a flap causes changes in the subcutaneous tissue and reticular dermis that makes it more vulnerable to secondary injury and (2) the reticular dermis responds to injury as two physiologically distinct layers, although it appears histologically homogeneous. The upper reticular dermis heals by reorganization, while the deeper reticular dermis heals by scar formation. The differing response to injury of these cell layers may in part explain the low safety margin in aggressive chemical peels.