Trichloroacetic acid peeling versus dermabrasion: A histometric, immunohistochemical, and ultrastructural comparison

BACKGROUND. Trichloroacetic acid (TCA) chemical peel and dermabrasion are beneficial methods for treatment of photoaged skin. OBJECTIVE. In this study, we evaluated the changes induced by these therapies on various structures of facial skin of nine dark-skinned patients (Fitzpatrick types IV-V; TCA, five patients; dermabrasion, four patients) demonstrating different degrees of photodamage. METHODS. Routine histopathology coupled with histometric computer-assisted image analysis was used to assess epidermal changes. Alcian blue stain was used to evaluate changes in glycosaminoglycans. Immunoperoxidase techniques with antibodies against types I and III collagen and elastin were used to evaluate quantitatively changes in collagen and elastic fibers, and their ultrastructure was examined by transmission electron microscopy. RESULTS. Similar histologic, immunohistochemical, as well as ultrastructural changes were observed in the two groups, including epidermal and dermal rejuvenation with new collagen deposition and normalization of the elastic tissue. However, these changes were more prominent in patients treated with dermabrasion than those treated with TCA. CONCLUSION. The results of this study suggest that beneficial effects of such modalities on facial skin were accomplished primarily by increasing the amounts of collagen I and collagen III and improving the morphologic appearance of collagen and elastic fibers.