Focal Trichloroacetic Acid Peel Method for Benign Pigmented Lesions in Dark-Skinned Patients E UN YOUNG CHUN, MD, n J UNG B OCK L EE, MD, w AND KWANG HOON L EE, MD n n Department of Dermatology, Yonsei University College of Medicine, and w Leejiham Skin Clinic, Seoul, Korea BACKGROUND. Benign pigmented lesions, including seborrheic keratosis, solar lentigines, melasma, and freckles, are com- mon disorders, and various treatment modalities have been tried. We suggest a technique consisting of focal trichloroacetic acid (TCA) peel applied by pressing firmly onto the focal lesions. OBJECTIVE. To evaluate the clinical effects of focal TCA peel on pigmented lesions in dark-skinned patients. METHODS. An analysis was conducted of 106 patients with benign pigmented lesions who were treated using focal TCA peel. Seborrheic keratosis was treated with 65% focal TCA peel, solar lentigines, and freckles with 50% to 65% focal TCA peel, and melasmas with 10% to 50% focal TCA peel. Patients had Fitzpatrick skin types IV–V. RESULTS. Patient treatment data indicated that 19 of 23 (83%) patients with seborrheic keratosis, 42 of 49 (86%) patients with solar lentigines, 8 of 14 (58%) patients with freckles, and 11 of 20 (55%) patients with melasma experienced a good clinical response. Good satisfaction rates in the seborrheic keratosis, solar lentigines, freckles, and melasma groups were recorded. No significant complications were observed. CONCLUSION. The focal TCA peel method presented in this study is a safe and effective modality for the treatment of benign pigmented lesions with no significant complications. E. YOUNG CHUN, MD, J. BOCK LEE, MD, AND K. H. LEE, MD HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. TRICHLOROACETIC ACID (TCA) has been widely used as a peeling agent for the treatment of a number of hyperkeratotic lesions, including actinic keratosis, solar lentigines, and the signs of photoaging. 1 The application of TCA causes coagulative necrosis of cells through extensive protein denaturation and resultant structural cell death. The depth of necrosis correlates with the concentration of TCA, which at medium level concentrations of 35% to 50% will penetrate between the superficial papillary and midreticular dermis. 2 Over the subsequent 5 to 7 days, the epidermis and superficial dermis slough, carrying away cytologically atypical keratinocytes and structurally compromised dermal connective tissue. As the wound heals by second intention, it is repopulated by deep follicular epithelium and newly generated connective tissue; thus, the skin is rejuvenated both clinically and histologically. 2 The histologic basis for the clinical effects of TCA peels has been well documented. Histologically, TCA peel results in the eradication of solar elastosis, which is replaced by a thickened, homogenized band of dermal collagen, which is complemented by the cytologic and architectural normalization of the epidermis. 3 TCA has been used in concentrations ranging from 10% to 70%, most frequently for light peel in concentrations of 15%, 20%, 25%, and 35%. There are increased risks associated with the use of higher TCA concentrations for deeper peels, especially in dark-skinned patients whose skin is known to possibly develop postinflammatory hyperpigmentation. 4 Benign pigmented lesions, including seborrheic keratosis, solar lentigines, melasma, and freckles, are focally distributed. In order to maximize the effects of TCA and to overcome complications such as scarring, hyperpigmentation, and hypopigmentation, we sug- gest a technique consisting of the focal application of higher TCA concentrations on the pigmented areas only by using a sharpened wooden applicator. The authors have used a similar technique successfully on acne scars over 10 years. 5 In this study, we varied the concentrations used depending on the state of pig- mented lesions. This technique can be used on focally pigmented areas rather than for the classic full-face chemical resurfacing. This method has the advantages of a more rapid healing time and a lower complication rate than conventional full-face chemical resurfacing because adjacent normal tissue and adnexal structures are spared. The purpose of this study was to evaluate the clinical effects of the focal TCA peel method on r 2004 by the American Society for Dermatologic Surgery, Inc.  Published by Blackwell Publishing, Inc. ISSN: 1076-0512/04/$15.00/0  Dermatol Surg 2004;30:512–516 Address correspondence and reprint requests to: Kwang Hoon Lee, MD, Department of Dermatology, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul, Korea, 120–752, or e-mail: kwanglee@yumc.yonsei.ac.kr.